Magnaflux Zyglo ZL-37 Penetrant - Level 4Magnaflux ZL 37 Level 4 Post Emulsifiable Fluorescent Penetrant Designed for critical component applications, ZL 37 is an ultra high sensitivity penetrant that excels in detecting fine, tight discontinuities in safety critical components, including titanium turbine parts and high stress investment castings. This Type 1 penetrant is non water soluble, minimizing the risk of washing away the penetrant from defects, ensuring reliable and dependable