Premium PH Meter Pen Digital PH Value Tester for Aquarium & Pool Water Monitoring Highly precise ultra-compact PH tester to check PH level of fluids in different industries & uses. Ideal for Laboratories, Hydroponics, Aquariums, Swimming Pools, Spas and Food & Beverage processing. EFFICIENT & ACCURATE as it simultaneously measure & display results due to its microprocessor tech. Includes PH 4.00 & PH 6.86 BUFFER SOLUTIONS, CASE & SCREWDRIVER for adjusting calibration trimmer. W/ Auto Temp Compensation (ATC), so no need to worry about the effect of temp change on PH level.