I have a Yamaha FZR1000 and the petcock has a square shape plastic knob. You pretty much need a set of pliers to turn it. Problem is, the bike I got had this knob broken off. I had to replace the petcock and decided a plastic wrench would help me operate it without damaging it.
I measured the petcock knob and printed a test piece to verify sizing. I designed a version with a handle to test functionality. It wasn't super comfortable to use, so I redesigned the upper part and this is nice to use.