pH Meter and TDS (total dissolved solids) meter combo. pH meter measures 0 to 14 pH range with a resolution of .1 pH and and accuracy of .1 pH.
Use the pH meter to check the pH of your water, mash, [test Star San effectiveness] and finished beer. The TDS meter could come in handy for checking your RO filter [See: Review – Portable Reverse Osmosis Water System] or for checking purchased distilled or RO water. Some water processors add minerals back for flavor. A TDS meter will allow you to make sure you’re getting what you want.
Update: Since this post was published the price, availability or promotion has changed. Check the product page for current description, price and availability. Also: Today’s Deals on Amazon
Also Consider: All Grain Tips & Gear || Hands On: 5 Stage Reverse Osmosis Water Filter by Reverse Osmosis Revolution