Box Quantity: 20. Length: 150 mm Diameter: 75 mm. Connections / Fixings: 3/4 inch barb style connections both ends to connect to the water line. It also has a 3/8 inch barb style connector to connect the the air pipe from the Ozone. Use 2 small metal clips or jubilee clips to hold in place as well as glue for best results. How it Works: Air is drawn through the Ozone on a venturi system. Water will pass through the jet sucking in air through the Ozone injector which will be connected to the Ozone. The top part is removeable to clean away scale and dirt build up during annual full service. Compatible With: This unit can be fitted to virtually any Hot Tub with a venturi system.