Make your best choice, LOCKLOCK zip ties! High Quality LOCKLOCK black zip ties are made of UV resistant halogen free nylon 66. Operation temperature is -40℉to 185℉with UL94V-2 flammability. Higher Tensile Strength The tensile strength of LOCKLOCK zip tie is 18 lb(4″), 25 lb(6″), 40 lb(8″), 48 lb(12″), higher than others.