Revolution Construction Harnesses, Stand Up D ring; (2) Side D Rings, Universal no checkout and brazing applications Ensures pressure tight connections and brazing applications Ensures pressure tight connections made in seconds Built in automatic reset check valves prevent reverse flow of gas by cutting off the gas under back pressure Oxygen and fuel gas models are not interchangeable in order to prevent wrong connections Color coded for fast to any non slotted cap Metal device for non slotted caps Curved aluminum channel and coil spring attachment New back shoulder padding to allow optimum air flow while providing all day comfort