1" Tri Clamp Sight Glass with Temp Resist Borosilicate Glass
1" Tri Clamp Sight Glass with Silicone Seals and Stainless Steel SS304 Borosilicate Glass.
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 3", and it is rated for a Maximum Pressure of 40 PSI.