A combination of easy cleaning and a clear field of visibility is provided by this specially constructed unit. With a butt-weld connection, these Series-MV sight ports allow the maximum view area in a minimal amount of space. An optional compact light source, type MV-ME, eliminates the added cost of a separate light port. Series-MV ports are particularly suitable for use in the chemical, pharmaceutical, food and beverage industries where frequent simple opening of the sight glass is required. Wipers are also available.