The Skull Piston Bob is a piece that you can find in the store edcapparatus.com with a lot of variants... either as a simple bead, carabiner, locator lamp, swivel and a long etc... of possible combinations.  In this video, I give you one more idea where to adapt the Skull Piston Bob. 

And if you don't have the tool artillery in your workshop, no problem, send it to me and we will do it for you in the workshop... We do it for you here