SaoSA glass hermetic seals are 100% solids, thermosetting, electrical-grade insulating glass. It is preformed in the shape of ring, which is exclusively for the use of sealing tubular heating elements. Attached please find the detailed photograph. We are the second company which created hermetic seals of solid glass, following ASAHI Glass Co. (a Japan Company). The quality and stability has been recognized by Sino-Japan Electric Heater Co., Ltd, which is the largest manufacturer of this field in the world so far. In choosing SaoSA seals, you are able to enjoy many benefits and advantages, Excellent Quality After testing for more than two years, SaoSA seals have be proved to be the same quality as ASAHI MG-2. It posses properties of Low Thermal Expansion Coefficient, High Heat-resistance, moisture-resistance and great sealing ability. Easy-to-Use SaoSA seals is 100% solid glass and thermosetting property. Lower Cost Our price is just less than 30-50% of average price in the current market. Looking forward to your favorable reply with keen interest and kind test is also welcome!