Menthol 16%. Maximum medicine; Powerful full speed pain relief. Penetrating relief from painful muscles and joints due to: Arthritis; Backache; Muscle strains and sprains. Greaseless; Stainless; Easy to apply. Maximum Strength Flexall combines the maximum allowable level of pain relieving medicine with a fast penetrating Aloe Vera Base to quickly speed powerful, fast acting relief to painful muscles and joints.