Black relay rack with 4-post, available in size of 84 x 19 x 18 in. Designed for mounting standard 19-inch rack components. RR-2164, RR-2173 and RR-2180 are heavy duty, very rugged relays racks with 8-inch side rails. RR-6119-3, RR-7019-3 and RR-8419-3 are economical, rugged relays racks with 3-inch side rails.