The Tracerline Vio-Blu dual-head LED flashlight, No. TP-9357CS, features a high-output True UV LED at one end and a super-bright blue light LED at the other. As a result, it provides optimal fluorescent response and contrast, regardless of the type of dye. This ensures that all leaks glow brilliantly. Leaks can be seen even without using the yellow glasses provided. The blue light LED works with all oil-based dyes, including difficult-to-fluoresce yellow dyes. With an inspection range of up to 25', this compact lamp allows for easy access into tight, cramped areas. Its anodized body stands up to years of use.