4-IN-1 CONCENTRATED FORMULA: Pure & Simple 4-in-1 Spa Shock contains a blend of oxidizers, sequestrants, clarifiers, and water conditioners for routine spa maintenance. Made with U.S. sourced components. DESIGNED FOR ROUTINE SPA & HOT TUB CARE: Formulated for regular use in hot tubs and spas. Suitable for common spa surfaces and equipment, including fiberglass shells, jet fixtures, filters, and heater components, when used as directed. ALL-IN-ONE FORMULA: You don’t have to be a chemist to maintain your hot tub with Pure & Simple 4-in-1 Spa Shock. Provides multiple water-care functions in a single formula for use as part of a consistent spa maintenance program. MEASURE, ADD & CIRCULATE: Add 1 oz per 100 gallons of water using the included precise measurement scoop. Circulate spa water for at least 15 minutes after application before use. MADE IN THE USA: Manufactured in the United States. Formulated for regular use in hot tubs and spas as part of a consistent spa care routine. Suitable for common spa surfaces and equipment, including fiberglass shells, jet fixtures, filters, and heater components, when used as directed.