hth Time to Shock Strips Test Strips 1.3 oz. (Pack of 12)The HTH test strips are the test strips that tell you when to shock. These test strips test for both free and total chlorine and give you results in seconds. The 25 test strips will help you take the guess work out of pool care. UPC: 073187011817 Manufacturer Part No: 1181 Brand Name: hth Sub Brand: Time to Shock Product Form: Strips Product Type: Test Strips Container Size: 1. 3 oz. California residents see Prop 65 WARNINGS