You need to check if a lens is going to fit the eyewire but you’re done sacrificing your finger tips trying to pinch the barrel closed. Instead of squeezing the eyewire and wrestling the eyewire screw into place, reach for the Eyewire Closing Plier, aka “sizing plier”. The pointed jaws fit securely into the eyewire barrel so you can comfortably draw the eyewire snug around the lens.