Aluminum alloy qq-a-250/4 alloy 2024-t4, anodize mil-a-8625 ty1 cl1 block; w/four cres ms16555-631 pins press fit into block at various pocations; o/a thk 0.375 in. Nom; o/a lg 2.115 in. Min 2.135 in. Max; o/a w 1.771 in. Min 1.791 in. Max; block cutout and chamfered on w