Specifications: Meets and exceeds NFPA standard 1961. Construction: Outer cover material: specially compounded red EPDM tough cover, Inner tube material: smooth black synthetic EPDM rubber, Reinforced with multiple plies of high tensile Aramid yarn providing flexible strength. 3/4" diameter hose is coupled with 1" threaded couplings. Coupled with female and male NST (NH) thread, chromed brass hole type couplings.