The Milwaukee pH600 Digital pH Pen keeps your pH in check with its simple sleek operation. pH levels are critical when it comes to nutrients, too high or too low pH levels could prevent your plants from absorbing the nutrients they need. The pH600 delivers fast and accurate results right to the easy-to-read LCD screen, displaying pH ranges from 0.0 to 14.0 pH. Measuring pH is a breeze, gently insert the probe into the solution and stir until results are displayed. Comes with a cap to protect the pen during non-use.