3" Tri Clamp Sight Glass with Safer Protected Temp Resist Borosilicate Glass
3" Tri Clamp Sight Glass with Silicone Seals and Stainless Steel SS304 Protection around Borosilicate Glass.
These are much safer and more durable then the ones that do not have the protection and the Borosilicate Glass. The stainless protection around the glass reduces the chance that the glass might shatter, and if the glass does shatter it will reduce the amount of flying glass significantly. Borosilicate glass is known for having very low coefficients of thermal expansion (~3 × 10−6 /°C at 20 °C), making them resistant to thermal shock, more so than any other common glass. This means that they handle heating, cooling and temperature changes much better than other types of glass.
The widest part on the body is 5", and it is rated for a Maximum Pressure of 40 PSI.