This acrylic sight glass tube is intended for use as a vacuum trailer, vacuum truck and frac tank sight glass. It's most popular use is as a visual fluid level gauge. The sight glass is a round, clear, acrylic extruded tube. It is durable, scratch-resistant and slightly flexible.The tube has an outer diameter of 2-3/8" and an inner diameter of 1-7/8" with a 1/4" thick wall. We stock this tube in a length of 72" (6 ft). This tube is priced and sold as a single 6′ tube. If you need a shorter length, we can cut this item down to meet your requirement. Please contact custom service for more details on custom lengths.