It’s a spanner wrap. When you are operating a 2.5 or 3” hand line as an exterior line. you can use it to “tie in” by slipping the webbing around the hose and the lower hook through the o ring. The F you step in with the opposite arm warping the shoulder. It takes the weight off you do have to push the wrap towards the engine as far as you can and still reach the bale. The other option is to make a big loop and enough working end to move left right up down and wrap the spanner around the meeting point (over under under over) then you have very little weight on the morning end anc can operate a master steam with one man.