Here's a video of made by 6 Precision of the Concept Tactical T.R.M.R. Impact Sound Device from RWA... "This Tactical Reloadable Maritime Ready ( T.R.M.R. ) Sound Device is an ergonomically designed multi-use grenade that utilises a twist to arm inertia recoil firing system, this allow for safe, fast reloading of the device without the need of levers and pins as used on conventional hand deploys devices. Manufactured from aircraft grade aluminium and stainless steel, harden and hard anodised to Mil Spec standards Multi munitions base system.

• 100% submersible and salt water resistant.
• Quick detach equipment mounting system for carriage."

You can find this in stock at RedWolf Airsoft.