My friend at camp sold his 2001 s/n and bought a new wakesetter so he gave me his 600 lb Sac, It came with a bag and the only label on it just Say BAG! Anybody ever heard of this oldskool Sac?

Its heavy duty and it has 2 connections on it

Anyway Do you guys just fill them up then place it over the back side and seat? Basically when these things are filled is it possible to move them around?