High Dielectric Plastic. Use To Protect Wire Within Flexible Metallic Conduit (Greenfield, BX). Insert One Bushing At Each End Of Conduit. UL Approved. No. 75400 - Fits Cable Range: 14/2, 14/3, 12/2 No. 75401 - Fits Cable Range: 14/4, 12/3, 6/1, 4/1. No. 75402 - Fits Cable Range: 12/4, 10/2, 10/3, 2/1. No. 75403 - Fits Cable Range: 10/4, 8/2, 8/3, 1/1. No. 75404 - Fits Cable Range: 8/4, 6/2, 6/3, 4/2, 4/3, 6/4.