This service is to Ultrasonic Clean Cylinder Heads.  This is very similar to hot tanking, but it works a quite differently.    This process can help clean when vapor honing is out of the question, and internal passages are needed work.  The ultrasonic will help clean inside water jackets, and small areas the jets in the hot tank just cannot reach.    This will only degrease the cylinder head, and will not give it a brand new cast finish like vapor honing or glass bead will.  The casting will still have some calcium deposited and oxidation.  The only way to rid aluminum of oxidation and calcium buildup is to blast it.