US CamelBak CBRN Hydration Training Kit, 4-piece, Surplus, unissued - Varusteleka.com
If you use the camelbak sippy bottles, you can get replacement parts : r/daddit
Amazon.com : Aquatic Way Bite Valve Replacement Mouthpieces fits Camelbak and Most Brands (4-Pack), with Shutoff Valve and Tube O-Ring for Hydration Bladder and Backpack Water Reservoir : Sports & Outdoors
Liquidlogic Camelbak Chute® Mag 32 oz Water Bottle, Insulated Stainles – Liquidlogic Kayaks