You need to mount a lens into the eyewire. Ideally when you’ve confirmed that the cut lens is the proper fit, you would simply screw closed the eyewire and be finished. More likely, you let go of the eyewire and the lens comes out. You preload the screw in a tweezer, reinsert the lens in the eyewire and hold the eyewire closed with your fingers. With your free hand, you pick up the tweezer and insert the screw into the barrel. Now, release the screw and pick up a screw driver, and attempt to get the screw threaded.
Let us interest you in an easier way. Close the eyewire around the lens using this plier. Then, while still holding the plier, insert the screw into the top hollow anvil. Insert the screwdriver blade through the anvil and engage the screw slot. Tighten the screw. Remove driver. Remove plier. Done!
Western’s parallel jaw design holds the eyewire closed more securely. This time saving plier reduces the possibility of damage to the frame by keeping the screwdriver tip from slipping off the screw head.