Met-L-Chek® FLP-1 is a special water based fluorescent (Type 1) penetrant concentrate designed for through leak testing and general metal working surface flaw detection. It is free of petroleum solvents and oils, making it safe for use on many plastics that may be attacked by more traditional inspection penetrants. Met-L-Chek® FLP-1 water based penetrant may be diluted with water to fit the inspection needs. The most common dilutions are 1:1 and 3:1, water to Met-L-Chek® FLP-1. For through leak testing or to enhance hydrostatic leak detection, dilutions of 1000:1 have been used successfully. The use of developer Met-L-Chek® D-70 will enhance flaw detection.