SPECS: 7⁄32"-40 thread. 3⁄8" or ½" STD Aperture Paks include three, 3⁄8" or ½" O.D. apertures: one each with .050", .093" and .125“ aperture holes. 7⁄8" x .050" Target Aperture Pak includes three, 7⁄8" O.D. apertures with .050" aperture holes. FP and 5D Big Game Aperture Paks contain three, identical eyepiece carriers which are used as large hole apertures for big game.
Catalog page 270