3L Tactical SOURCE Hydration SystemHigh performance 3L hydration reservoir system. Exclusive 3 layer coextruded Polyethylene construction with Taste- Free, low maintenance, Glass-Like liner. SOURCE's Glass-Like Film is 2000% smoother than standard TPU films, with virtually no difference from glass itself.Care-Free System Glass-Like Liner with Grunge-Guard antimicrobial technologies eliminates the need for cleaning.