The Extech PH10-P Pint Size Bottles with Pre-made 10pH Buffer Solution (2 Bottles) is an optional accessory designed for use with the PH10, it's easy to use and it comes in convenient pint size plastic bottles. The already made fresh pH buffers for calibration include a helpful table that shows what the pH value should be vs. the temperature of buffer solution measured. The PH10-P includes features such as a rinsing solution used for cleaning off pH electrode after taking next measurement from different solution to prevent contamination, as well as a convenient pouch that eliminates the need for a cup to store buffer or rinsing solution. Convenient pint size conductivity standards calibrate your conductivity meter to optimize its accuracy.