The ATB cap is designed to fit on Nalgene ATB bottles. It will fit on both the 22 oz ATB and the 32oz ATB. It also fits the 12oz Mini-Grip/Grip-n-Gulp bottles. So if you want to upgrade your kid to a more grown up cap this is a good option. The ATB cap doesn’t really fit on the 32oz wide mouth bottles. You can screw it on but the â??skirtâ? on the ATB closure is long enough that it bottoms out on the neck ring of the bottle. That prevents a perfect seal. So if you do it the bottles are not as Leakproof as the standard Nalgene closure. This cap is made in USA and is BPA free.