Features a revolutionary microscopic sponge encapsulation system that delivers the benefits of salicylic and glycolic acid in a oil free gel formula. As the microscopic sponges continuously absorb excess surface oils, users will notice a rapid improvement in their acne condition. Acne Gel I is half the strength of Acne Gel II, but either strength is very potent. It is recommended to start with Acne Gel I and then increase to Acne Gel II if necessary. Each 2 oz bottle will last approximately 4 to 6 months.