Vibram Five Fingers KSO - Keep Stuff Out - Toe Shoes

The Vibram Five Fingers KSO (KSO stands for "Keep Stuff Out") has been one of the most popular models of Vibram Five Fingers to date (Jump to posts on the KSO below!). It's closed top design sets it apart from the open-topped Classic and the open- and strap-topped Sprint. Some might argue the KSO put "Toe shoes" on the map due to it's popularity among runners. Like all Vibram Five Fingers models, the KSO has five separated toe compartments for each toe that allow the foot to splay on contact with the ground.

The Five Fingers KSO has no arch support and a minimal amount of cushioning or padding — it is slightly thicker than the Classic and Sprint which have zero insole (the KSO has a 2mm EVA insole). Many, many minimalist runners "cut their teeth" with the KSO — running 5KS, half-marathons, full marathons, and even ultramarathons in the KSO. That said, the KSO is also a favorite for exercise, casual wear with jeans (or shorts), and also for travel.

Model specifics

Here are the technical specifications of the Vibram Five Fingers KSO straight from Vibram:

Featuring a thin, abrasion-resistant stretch nylon and breathable mesh upper that wraps your entire forefoot to "Keep Stuff Out." A single hook-and-loop closure helps secure the fit. A non-marking 3.5mm Vibram TC1 performance rubber sole is razor-siped for a sure grip, and a 2mm EVA insole enhances plating protection and comfort.

KSO IS BEST FOR: Running, Light Trekking, Climbing/Bouldering, Fitness, After Sport, Water Sports, Yoga/Pilates & Travel

The standout features of the KSO include:

  • Closed top providing a fairly tight "seal" around the ankle. The KSO manages to "keep stuff out" by way of this seal leaves it looking somewhat like an ankle sock.
  • The KSO has a 2mm insole, which reduces "barefoot feel" as compared to the Classic or Sprint. Many users don't notice this small amount of cushioning. Some find it more comfortable for more varied surfaces such as trails.
  • The KSO is the most popular model for men!

Sizing and fit

If you've never sized your foot for Vibram Five Fingers, you need to consult the Vibram Five Fingers sizing chart (image) and measure the length of your feet as presecribed. Vibram sizing does not correspond to standard shoe sizes!

If you've sized in Vibrams before, note that KSOs size slightly larger than the same size in the Classic or Sprint models. So a 43 KSO will fit larger than a 43 Classic or 43 Sprint. For this reason, Vibram prescribes you size down in the KSO compared to the Classic or Sprint models. Generally, it is better to size up if you're in between sizes — you don't want your toes bending out of lack of room! Also, the KSO's closed-top design means that if you have particularly high arches or "high feet" the KSO may not fit properly and you might consider the Sprint or the Classic. Finally, some have anecdotally observed that black KSOs size smaller than other color combinations.

Read (and see!) more about the Five Fingers KSO via these reviews:

Modifications and other considerations:

Okay, I want some KSOs. How much are they? Where can I get them?

The KSO retails for around $85 and can often be purchased with free shipping from most online retailers. Find the Vibram Five Fingers KSO in stock via the Store or subscribe by email to inventory alerts.

Of course, there are other barefoot shoes worth checking out!

More Vibram Five Fingers KSO posts below —

Tags: kso

Vibram FiveFingers: Engaged!

James and Ashley take Captain Picard's order to Engage! at the Garden of the Gods in Colorado.  You can see they're sporting FiveFingers KSOs and the Bikila LS!
James and Ashley take Captain Picard's order to Engage! at the Garden of the Gods in Colorado. You can see they're sporting FiveFingers KSOs and the Bikila LS!
Justin (not me) sent in a few photos his fiancee Ashley and he took for their engagement. Congrats, you two! Check'em out: And here's what Justin had to say about the photos: Hello, Our names are Justin and Ashley and we took some of our eng… more »

Running in Stem Natural Origins Shoes and KSOs

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Nathan sports his KSO FiveFingers (and takes along his Merrell Barefoot Trail Gloves) on a hike to the top of Mt. Leconte in Tennessee.  Note his wife sporting the Merrell Barefoot Pace Gloves!
Nathan sports his KSO FiveFingers (and takes along his Merrell Barefoot Trail Gloves) on a hike to the top of Mt. Leconte in Tennessee. Note his wife sporting the Merrell Barefoot Pace Gloves!
In the reader mailbag (a few weeks back!) I got the following note from FiveFingers fan Nathan on his KSOs: This past week I hiked with my wife and some of my family to the top of Mt. Leconte in the Great Smoky Mountains of Tennessee. I wore my VF… more »

FiveFingers for Dancing the Night Away at Senior Prom

Spencer and Jana show off their choice of Senior Prom footwear--toe shoes!
Spencer and Jana show off their choice of Senior Prom footwear--toe shoes!
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Special Forces, Jumping out of Aircraft in FiveFingers KSOs

Special Forces, Jumping out of Aircraft in FiveFingers KSOs
A U.S. Army soldier with the 10th Special Forces Group and his military working dog jump off the ramp of a CH-47 Chinook helicopter from the 160th Special Operations Aviation Regiment during water training over the Gulf of Mexico. Tech Sgt. Manuel J. Martinez/defense.gov
U.S. Army Special Forces in Vibram Five FingersAfter the success of the Bin Laden mission, NPR ran a story reporting that a dog may have been part of the raid. While there has been a lot of buzz about the dog having titanium teeth, it didn't take long… more »

A Vibram FiveFingers and Barefoot Wedding

Gidds and her husband
Gidds and her husband at their wedding.
Gidds sent us the following story about going barefoot at her wedding with the groom wearing Vibram Five Fingers black KSOs, of course.I started wearing VFFs last year around Memorial Day because I have a lot of foot problems but I strive to have a… more »

Natural Running in Huaraches and Vibram Five Fingers

James, Al and Spud
James, Al and Spud at the 2011 Pensacola Double Bridge 15K Run.
James and his buddies have been gradually increasing their miles and competing in longer races in preparation for a half marathon. James sent us this story about their last run in the 2011 Pensacola Double Bridge 15K Run:Fellow barefoot runners a… more »

Vibram Five Fingers to Lose Weight and Get in Shape

July 12, 2009
Chris says, "Here's a photo of me in the VFFs July 12, 2009 at Carolina Beach. It's a little frightening to look at even for me."
The BirthdayShoes.com forum is chock full of great information from the most passionate minimalist shoe fans around. Sometimes the stories are so compelling that they need to be published here on the main blog. Chris's story is one of those. He has been… more »

Pregnant Runner Loves Her Vibram Five Fingers KSOs

Josephine in her KSOs
Josephine out for a spin in her Vibram Five Fingers KSOs.
As you can see from the picture above, there aren't many things that keep Josephine from going out on her daily run in Vibram Five Fingers KSOs. Pregnancy and snow didn't stop her. Here is Josephine's amazing story:I'm almost 5 months pregnant … more »

Surviving a 7 hour Fitness Camp in Vibram Five Fingers KSOs

7 Hour
Coach Jake, Lindsay (second closest) and others enjoy "7 hours of non stop fun".
Jake Morrison, of PA Fitcamp, introduced his client Lindsay to Vibram Five Fingers as a way to help her get fit. Lindsay shared her fitness journey with us in the following testimonial:My VFF StoryLindsayI had chronic knee problems since I wa… more »

Couch to Half Marathon in 8 Months wearing Vibram Five Fingers

Jeremy in his Bikilas
Jeremy in his Vibram Five Fingers Bikilas at the Dubai Marathon.
We love getting stories and photos from BirthdayShoes readers. The following post came in from Jeremy who is a Vibram Five Fingers Fan in Dubai. If you would like to send us your photos and a brief story that goes along with them, here is a guide on just… more »

First Marathon in Vibram Five Fingers KSOs

Chris in his KSOs
Chris at the 22.5 mile mark and after he finished.
After doing no marathon training, Chris recently ran his first marathon in Vibram Five Fingers KSOs and finished with a darn good time. You may remember Chris from when he ran the Baltimore Half Marathon with Bien. Here's what he sent us about running th… more »

New 5K PR in Five Fingers Bikilas

Matt in his Bikilas
Matt running in his Bikilas at the Houston, TX Great Pumpkin Fun Run (5K)
Matt has a nice collection of Vibram Five Fingers that he has been wearing for quite a while. He sent us this note on how they have been working for him:Just wanted to share a quick story since I finally have a good picture with my VFFs. I wear my… more »

Transatlantic Cruising Five Fingers Style

Bill jogging
Bill jogging on the Promenade deck.
Bill decided to get a little marathon training in wearing his Vibram Five Fingers KSOs while cruising the Atlantic. Here's what he shared with us:I thought I would share some pictures my wife took of me in my KSOs on our cruise on the Norwegian Sun… more »

Dr. Jawa Runs his First Marathon

Dr. Jawa and his wife
Dr. Jawa and his wife running the St. George Marathon.
Dr. Jawa, is a long time reader and contributor to our blog. You may remember Dr. Jawa doing headstands, teaching in black KSO VFFs, running a half marathon in Las Vegas, or on vacation in Jamaica. Dr. Jawa recently continued his adventures in Vibram Fiv… more »

Allison's Big Toes are in Vibram Five Fingers KSOs

Allison's Big Toes are in Vibram Five Fingers KSOs
Reminders for the race!
Recently, Allison ran her first half marathon in Vibram KSOs, her second-ever half marathon. She created the blog, AllisonsBigToe.com for the express purpose of documenting her 16 week training for this event and transition to running in Vibram FiveFin… more »

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Rafael at the Nautica Malibu Triathlon
Rafael swimming, cycling, running and finishing the Nautica Malibu Triathlon.
Though we suggest all runners transitioning to Vibram Five Fingers take their time and make a very gradual transition, Rafael ran in the Nautica Malibu Triathlon after just six weeks in Vibram Five Fingers.My name is Rafael from Sacramento, CA. I… more »

UK Rat Racer Wears Vibram Five Fingers KSOs

Dave at the UK Rat Race
Dave walking the plank and sliding to the finish at the Rat Race.
Extreme races are the rage these days and Vibram Five Fingers fan Dave recently ran in a UK event called the Rat Race Urban Adventure. He donned his KSOs and went for it! Here is what Dave had to say:A couple pics of me from this last weekends River R… more »