GroStar GS1 pH PenIncludes: pH 7 & pH4 calibration solution (50ml bottle each), KCL storage solution (10ml bottle), lanyard and user manual Measures pH and temperature Premium probe technologies and materials ensure high accuracy and durability with minimal maintenance Easy to use design and fast calibration adjustment Double junction replaceable probe, so you dont have to discard the entire pen when the probe reaches its end of life Large 3 color backlit screen gives