Kelway pocket size soil tester needs no chemicals — simply insert in soil for instant reading! Push button switch for measuring pH ranges from 3.5 to 8. Can be calibrated to maintain accuracy. Also measures soil moisture (humidity). Accuracy +/- .2 pH in acidic soils, not designed for alkaline soils 7.5+ pH. Case included, 6 1/2” long. Tests soil in 3 minutes, no battery or chemicals, 6 ½in. overall length, 8oz. overall weight. Complete with carring case. PH range from 3.5 to 8. Used for testing soil not liquids. Manufacturer promises these are accurate to within +/- .2 of a PH number in acid soil. These are not made for saline or alkaline soil with a pH over +7 Manufacturer supplies a 6 month warranty against defect in material or workmanship.