Here's what other sites are saying:
For the purist looking for a sleek, low-profile look and a 100% stainless environment, the Stainless Flat Cap is the way to go.
All styles of Klean Kanteen Caps are available and they include the Poly Sport 2.0, Poly Loop, Poly Flat, Stainless Loop and Stainless Flat caps that work with all sizes of the Classic Klean Kanteen. All caps and lids are interchangable with all sizes of Klean Kanteens. Stainless steel loop and flat caps are available for those who prefer that only stainless come in contact with their beverage. Customize your Klean Kanteen collection to your liking or simply replace a lost top. All Klean Kanteen caps are made from polypropylene, a safe plastic that's free of BPA, phthalates and other toxins. The revolutionary Sport Cap 2.0 effortlessly delivers a high flow rate that makes it easy to drink from your bottle without removing the cap. The Loop Cap is totally leakproof and has a durable attachment point so you can clip it on to just about anything. Flat Cap is low-profile, unobtrusive and leakproof
- Tahoe Mountain Sports
You've got the stainless bottle, but what about the cap - make sure your drink never touches plastic with the Klean Kanteen Stainless Flat Cap. The inner threaded part of the cap is food-grade stainless steel and the sleek outer part is made of BPA-free polypropylene.
- Mountain Gear
Designed to give you a low-profile option that doesn't take up much room. It's the choice for itty bitty purses, jam packed bags or those times when you want a smooth, simple look. Creates an all-stainless interior. Interchangeable with all Kanteen(R) Classic bottle sizes. Should be handwashed. Cap is leakproof. Made using BPA-free polypropylene (pp#5) on the outside, the inner, threaded part of the cap is 18/8, food-grade stainless steel so your drinks never touch plastic. It's the same high quality stainless steel we use to make our bottles, so it's totally free of BPA
- Rocky Mountain Trail
Klean Kanteen Stainless Flip D-ring Cap
Klean Kanteen Stainless LPT Bamboo Cap
Klean Kanteen Flat Cap
Guyot Designs SplashGuard
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$15 - $19