Receptacle boxes are made of bakelite. 7060 has two 1/2" knockouts in each end. 7090 has two 5/8" knockouts in each end. No clamps. Dimensions listed by L x W x D. Inside: 2-13/16" x 2" x 1-9/16" Cut-out:3-5/8" x 2-1/4" x 1-3/4".
