Hign-concerned Chemical:NoneOrigin:Mainland ChinaThis kit will allow you to run GM short LS2 injectors in a application where a LS1 injector height would normally be used. This kit will also allow you to run GM LS3 injectors or Bosch 210 in a application where a GM Truck injector height would normally be used. These adapters are CNC cut on a lathe for an incredibly precise fit and a leak free seal. We also include oil/gas/solvent resistant o-rings for a long lasting seal. These spacers add approximately 0.47" to each injector. The spacers get mounted on the top of the injector. If you were to put them on the bottom, the spray pattern of the injector would get messed up and the car would not run right.