Nylon 66 per mil-m-20693, comp a, type ii; 4.40 in. Outside dia. Before slotting; 3.59 nom in. Inside dia; 0.33 in. Thk; the slot is 0.030 in. Wide angled at 45 degrees; item used on 5 in. 54 caliber hifrag projectiles - bl&p mk109 mod 0, he-ir mk84 mod 0, and he-mt/pd mk82 mod 0