Easily view liquid movement and level changes from a distance—these sights have an indicator ball inside the glass window.

View tank contents from multiple angles through the plastic domed window.

Continuously monitor oil quality through the clear plastic reservoir, and use the attached drain valve to remove water accumulation.

Often used in kilns and other heating equipment, these sights have a quartz window that can withstand temperatures up to 1600° F. They're also known as peep sights.

Press these sights into a hole in your tank wall; no additional mounting nuts are needed. They mount from the outside.

Weld these sights to single-wall tanks.

Add a window to your high-vacuum system. With a pane of borosilicate glass sealed inside a high-vacuum CF flange, these sights bolt onto vacuum chambers, tee fittings, and manifolds.