¼" outside diameter, 3/16" inside diameter (standard size) Air tubing sold by the footUse to connect an air pump to air stones, fits with most any air pumps, Air Tubing fittings and air stones.
¼" inside diameter tubing that fits onto commercial air pumps and the Optigrowth Co2 Injection Kits.** note ** this tubing is too wide for the Titan CO2 Injection kit (for that kit simply choose the 1/4" outside diameter air tubing)
