Verifiers are to be used with scope lenses with pins. The Verifier peep has lens in it similar to the ones in your reading glasses that will allow you to see your sight pins better on your hunting sight. Don't let changes in your vision compromise your ability to make the shot. The verifier lens sharpens the picture so pins and quarry are easy to see. The 1/8" verifier is for use in the 749-37, 749-37H, 749-45, 749-45H, 750-1 peeps. It will also fit in the 749-42LH and 753-1 peep with aid of screw in reducer (753-3). We recommend use of dual hex wrench for inserting verifiers into your peep. The Verifier is 1/8" or.25" aperture which fits the 1/8" Super Ball peep and the 1/8" or.25" Super Peep Hunter. The greater the number the stronger the power.