It is.... it’s the exact same pen.... but it always seems to take a long time to show that stabile PH reading.. my tap water is 8.4 so I experiment to see how much Earth Juice or lemon juice I need to bring it to 6.4 to 6.6.... as I dip into the water, it starts dropping .1 or .2 but when it’s getting close to it’s final reading, it slows, takes another 7-10 seconds before I’m sure it’s not going to fluctuate. I’m just making sure that with all of the care I try to provide it, is working correctly and that spending $150.00 for it and the storage solution versus the $7.00 one I used all the time...and reads pH in about 4 seconds, is really worth it. I’ve never had to address wild pH problems. However, I monitor it frequently. A side by side calibration of both and a measurement, did give the same pH measurement so there has always be a question in the back of my head. Ultimately, wondering if they all seem to work the same way. The only other pH management I’d ever used were the drops and that color chart.