Food grade EVA (Ethylene Vinyl Acetate Copolymer) Camel Bladder insert. 
Dimensions: 
41 x 18cm (16.15 x 7.09in), capacity 2.5 Liter/84.5 oz 

** Please wash bag and tube with hot water before using. DO NOT use water that is hotter than 50 degrees Celcius. NOT RECOMMENDED to fill with milk, juice, wine, beer or any other liquid that could stick and make cleaning difficult.