Professional design Large Format Lens Wrench for secure installation/removal for Copal, Compur, and Prontor 0/1/3 lens retaining rings with steel durability Essential tool for large format photographers and camera technicians requiring precise maintenance of modern view camera systems Craft from corrosions resistant steel with vibrations polishes edges to scratches on lens boards and shutter surfaces during adjustments Compatible for all standard lensboard thread pattern, this heavy duty lens tool combines antislip ergonomics with permanent marked identification for errorfree shutter model matching Safely tighten/loosen lens flanges rings in studio setups or field repairs without damaging delicate shutter engravings, thanks to etcheds size indicators