The Thrif-T Luber Orifice Fittings are available in three (3) configurations and 10 size ranges. Each size passes twice as much flow as the size below it. Each is equipped with a sintered bronze filter, tapered spiral orifice pin and built in check valve. The sintered bronze filter and tapered spiral orifice pin makes the units more resistant to blockage from contamination than the designs used by competitive units.