Most black or red standard heater hoses have a single layer of reinforcing yarn provided by a single braid or two opposing spirals of fabric.
G302 has two separate layers of two spirals each, separated by a blue insulating layer.
The extra reinforcement provides higher burst and kink resistance.
Thermal heater is designed to meet the high heat and ozone conditions found under the hoods of todays automobiles and meets SAE20R3 D2 specifications.