Tubing is same diameter as reinforcing rings on the standard taper joint. The rings permit penetration by the clamp cushioning material, and permit firm support without the need for excessive pressure on the joint; also, strain on the joint is reduced from expansion due to temperature increase. Properly clamped, the joint tends to remain cooler, with less tendency toward lubrication loss. Better balanced design, more resistant to thermal shock than heavy wall. No holdup below joint, ideal for flask necks, receivers,etc.