Defend Ultrasonic Cleaning Tablets - 64 Tablets/Box, 2 Tablets/1 Gal. Biodegradable, non-chlorine, non-corrosive formulation that contains fast acting protease enzymes, assist in the removal of blood, bone, tissue, food particles and other soils that may be resistant to chemical detergents. Contains a pleasant fragrance and is a neutral pH. May also be used as an instrument pre-soak or as an evacuation system cleaner.