1. Both body and bonnet are integrally forged, high strength, nice mo-del, reliable material.

2. The middle cavity is of a self tightly sealed structure, the higher the pressure, the better the tightness. Unique stainless steel seal-seal ring, easily disassembled and assembled and reliably sealed.

3. The stem surface is processed with the way of extra-strength caused sealing and wear-resisting, wearable, small open-close friction, making it surely without leak.