anderson FD601 Fluorescent Leak Locating Dye, 8-OunceFluorescent leak locating dye has a special concentrated dye that holds together underwaterIdentify leak as locating dye is for the detection of leaks in light colored poolsWorks on plaster as well as vinyl and painted pools and can be refilled with leak master dyePlastic needle allows for precise dye placement without creating unwanted currentsComes in fluorescent color; available in 8-ounce pack