The Bluepen pH is an accurate, easy-to-use, hand-held electronic pH tester with built-in thermometer for soils, liquids, foods, chemical solutions, etc. This unit is less than a year old and was only used a handful of times. I no longer have a need for it. New ones sell for about $90 on Amazon; this one can be yours for only $40. Note, however, that this only includes the pH pen–it does not come with storage or calibration solutions, which are necessary for accurate readings and are available from Amazon and other retailers.