Black Base Pad
A 752-style pad with Decelerator material to soak up recoil, and a hard insert at the heel to slide smoothly over clothing.
Big Book Catalog, Issue:72, Page:406
SPECS: Small, 1.68" (4.3cm) x 5.30" (13.5cm);
Medium, 1.80" (4.6cm) x 5.50" (14cm); Large,
1.92" (4.9cm) x 5.75" (14.6cm). .8" = 20.3mm, 1" = 2.54cm.