"Heavy-duty pre-fabricated CM29 reducers (.187Ø) are available in standard configurations with a grid pattern of 2 x 4 and a depth/height of 2 or 4 (24-18, 18-12, 12-8 and 8-6 are standard widths). CM29 is UL listed as a ground conductor and each section includes interconnecting hardware."... Click here for more info on CM29 Heavy-Duty Reducer 4depth 18 to 24 W.
