Head Gasket - HKS 1.6mm - 1JZ-GTE EngineHKS Multi Layer Steel Head Gasket for 1JZ GTE Engines Stopper Type 1. 6mm The HKS stopper type gasket forms a high pressure seal around the combustion chamber through the use of stoppers which create a step within the gasket for optimum sealing. By making the stopper part of the plate also allows the fold to be smaller while maintaining structural integrity. One side of the plate is completely flat meaning that it can be layered with the stopper to