Axle Cover Installation KitChrome socket head screws: 2 pieces 1/4-20 thread x 2-3/4"; 2 pieces 1/4-20 thread x 1-1/4" Flat washers: 2 pieces - 10.9 mm OD x 6.75 mm ID x 1.5" thickness O-ring: 1 piece - 9.2 mm OD x 2.62 mm thickness Aluminum threaded rod, grinds finished - 1 piece Left/Right base (Aluminum die cast - vibratory grinds finished).