These are the sight Glass Assembly which are used to check the flow in line of process plant. They are generally available in MS with Powder Coated and SS 304 or SS 316. There is Teflon Bush which is installed between the frame and glass so it makes the perfect sealing and the product does not meet the metal. These are generally come in size 1’’ X 6’’, 1.5’’ X 6’’, 2’’ X 6’’, 3’’ X 6’’, 4’’ X 6’’, 6’’ X 6’’.