0.375" hole diameter H2 equally spaced projections extending from bearing surface each side of centrally located hole 0.125 in. wide by 0.188 in. high; 2 holes 0.043 in. dia, thru washer periphery
0.503" hole diameter navy special project 2 projections equally spaced on washer face, 0.125 in. wide by 0.086 in. high; 2 holes 0.043 in. dia, thru washer periphery