1. It has a scratch and oil resistant glass. Sealing is achieved by attaching an Oring gasket around the glass, not on the front face edge. Therefore sealing is not affected by axial pressures.
2. The gasket is not lost as it is contained in a groove. Also, this groove prevents the gasket from coming off when the plug is tightened.
3. Since the gasket at the bottom is also in a channel/enclosure, it is not affected by external factors.
4. Since the gaskets are inside the channel, they present a more aesthetically pleasing appearance than their counterparts.
