The sight glass of fluid sight glasses EN 543.4 is embedded in the body during the injection process and it is therefore absolutely leak tight.
These fluid sight glasses use the prismatic effect of a cat’s eye to give a clear indication of the fluid level unaffected by fluid color or fluid viscosity. The advantage of this effect is particularly obvious in the case of underfilling or overfilling and for inspection under unfavorable light conditions.
The seal is embedded in a radial recess, and thus cannot be squeezed out during tightening.
For wall thicknesses below 0.16 in (4 mm), use thin hexagon nuts GN 7430.