Test pen specifications are as follows:Size: length 14.2 �� width 2.3 �� thickness 1.3 (CM).Wide measurement range able to measure 1-9999PPM.Application temperature at 0-50 degrees wide work， can be stored at minus 30 degrees.LCD large-screen LCD window waterproof design， easy to watch， durableLR44 battery * 2 (not include)10 minutes without operation of automatic shutdown function to save the battery.pen designed electrode can be inserted directly measured in the test solution， pen loops can also be used as the test solution container to use， very convenient.Due to sophisticated measuring rapid bare-style sensor， 5 seconds to complete a measurement.�� 1% accuracy error， high precision titanium probe measuring water，Magnetic interference from waterAutomatic temperature compensation can be automatically converted indication to show the value of 25 degrees.Note: Sometimes the TDS tester can not turn on， please check the battery case， there are 2 Resilient metal touch pad who transport the current， sometimes it is on the high position， so it can not touch the Circuit board when closing the battery case， so the tester can not turn on. Packing include:1 x Tester