Style RES1. Used in conjunction with The 'Cooler Bleeder and the Series 2 Adapter.  Machined in the USA from high quality Delrin,  this inserts into the mini reservoirs found in many Chevrolet, Cadillac, and Saturn vehicles, while simultaneously blocking off the overflow line.  This reservoir style, GM part 22697069, is also used in many retrofit intercooler kits.  Used in place of General Motors / Kent Moore special tool J46143.  See Connection Chart for exact fitments
 
Note:  Hand assembled in the USA, there may be cosmetic tooling marks on plug from assembly.