ENSURE YOUR POOL AND SPA HAS THE RIGHT LEVELS OF CHEMICALS IN THEM WITH THE FLOWCLEAR� POOL AND SPA TEST STRIPS BY BESTWAY�. THESE 3-IN-1 TEST STRIPS TEST THE FOLLOWING: -FREE CHLORINE ,PH,TOTAL ALKALINITY. WITH AN EASY COLOR-MATCH SYSTEM, YOU WILL INSTANTLY KNOW WHAT CHEMICALS ARE IN NEED OF ADJUSTING. THE STRIPS MEASURE FREE CHLORINE FROM 0 TO 10 PPM, ALKALINITY FROM 0 TO 240 PPM AND PH FROM 6.2 TO 8.4 WITH INSTANT RESULTS. THE BOTTLE CONTAINS 50 TEST STRIPS AND HAS AN 18 MONTH SHELF LIFE.