6irregular shape; 1.375 in. Thk, 4.500 in. H o/a, 2.375 in. H to 1st step, 14.500 in. W at base, 3.500 in. Bore radius; 0.875 in. Drilled hole from top of 1st step through to base, one hole through each step; u/o forward low pressure units, port and starboard