Be confident in your purchase we're an Authorized Coral RX Dealer. How cool is that?!?!? Features: Fast, accurate results with digital LCD readout Easy measurement: just place the probe in the sample, gently stir and wait for the reading to stabilize Simple one-point calibration with an easy-to-use trimmer located on the back of the pH tester to protect from accidental splashes Cap to protect the pH sensor and keep it wet when stored upright Low power demand for extended battery life (batteries included) The Milwaukee pH600AQ compact pen tester is specifically designed to help maintain aquariums and aquaculture. Keeping the proper pH improves results for aquarium fish and quality in a range of fish raised in aqulculture. Use digital accuracy to keep pH in your target range for better results.