These convenient syringe style testers are pre-filled with a special concentrated dye that holds together underwater. Six inch plastic "needle" allows for precise dye placement without creating unwanted currents. Dye testers can be re-filled with Leakmaster Dye available in 8 oz. bottles.
20 Blue and 20 Flourescent yellow.
Most economical way to buy Dye Testers. Great for larger service departments or retail sale.