Spotcheck® SKL-4C is a water based, water washable red penetrant. It appears dark purplish red under visible light and fluorescent orange under black light to give it a dual range inspection capability. SKL-4C can be diluted infinitely with water but is generally recommended at 1:1 dilution.

Warning! Penetrants attack and even dissolve many kinds of plastic pipe. Polyvinyl chloride (PVC) pipe is especially vulnerable, and can crumble after only a few days of exposure. Even diluted penetrant rinsings attack it rapidly. ABS plastic pipe is nearly as sensitive. When installing plumbing to handle penetrant rinsings, use metal pipe.