The Two Little Fishies Airline Hose Fittings, 12-Piece Kit, includes: (3) tees; (3) elbows; (3) crosses; and (3) joiners. These micro airline fittings are for connecting standard airline tubing for devices such as airstones, filters, protein skimmers, ornaments, etc. Use teflon plumbing tape on threaded fittings for water applications. Secure barbed connections. Excellent for low pressure installations.