Optiloupe® For use with Donegan Optical Optivisor® headband magnifyer (headband magnifier not-included). Simply remove the fastener which holds the lens plate to the visor and replace with the threaded stem of the Optiloupe®. The stem serves to hold the lens plate and the Optiloupe®. Easily attaches to either the left or right eye of any Optivisor®. Increases magnification by 2½ x.