I have something similar to this from Blackhawk. It's both a belt w clip on and converts to a shoulder rig with the included straps. Never used it because I got a dropleg which I like better and 2 vests with built in shoulder rigs.
CWO-4 US ARMY Ret./Med.
Proud to be a Soldier, Proud to be a Night Stalker!
The 160th Special Operations Aviation Regiment(S.O.A.R.) The Army's Taxi for Special Operators *NSDQ*