SMB5 with over-pressure relief valve: reusable surviballoon with a unique two-layer design

The outer layer is made of strong nylon with PU coating which protects the inner air cell where gas will be retained; use of an octopus/ air gun can effortlessly inflate the SB-5, and the special opening will automatically trap all incoming gas when full;the opening end of SB-5 contains counter weight to keep it upright in water