Umiin 0.05pH High Accuracy Pocket Size Digital PH Meter Tester with ATC and Backlit LCD,Red Great for all pH testing applications including aquariums, swimming pools, tap water, beverage etc. Handheld pen-type design for portability and convenience with carrying case Automatic Temperature Compensation: ATC accounts for changes in temperature automatically Full pH 0-14 measurements;0.05pH highly accuracy; 0.01 pH resolution; Reliable and quick readings on Backlight LCD Easy to calibrate with pH 4 & 6.86 buffer packets included