The Eisco Labs Beehive Shelf is a porcelain stand used for gas collection in pneumatic troughs, supporting an inverted gas-collection vessel above the trough water level so that gases evolved from a delivery tube can rise into the vessel. Constructed from porcelain and glazed inside and out (except the bottom edges and top), the shelf provides chemical resistance and easy cleaning. The shelf stands 2.5" tall, with a 4" inner diameter and 4.6" outer diameter. The top center hole measures 0.8" in diameter, and the bottom opening is 0.7" tall by 0.6" wide.