D-350 is a hi-temp developer used to enhance penetrant indications on parts
at elevated temperatures, temperatures up to 3500F (176.70C). D-350 is the developer
step in a three part high temperature system (KO-17 hi-temp penetrant and a KO-19 hi-
temp remover are the other materials of the hi-temp system). D-350 complies with low
sulfur and low halogen requirements.