Precision Machined Parts. Solid Brass Construction. Unravel proof pads. Kaydee Rapido couplers fitted. Easy Fill Design. Leak proof valve and fill port. Heavy weight does the job. Quick Change Pads. Drag pads won't catch on complex trachwork. These all brass tank type track cleaning cars beat all others in the "white glove" test or your money back. An initial supply of pads is included. Solvent proof design (brass construction). Multi directional (pushed or pull). Controllable dispensing rate. Body mount Kadee couplers. Shorting resistant delrin trucks. Both solvent and abrasive cleaning options.