Review on 📏 Enhanced Precision: Extra Large Buffer Calibration Kit - The Ultimate Tool for Accurate Measurements by Neil Biondo

. After using them for a few months, I noticed something was wrong. It's wine season and my neighbor's pH levels didn't match mine. I dug up some old expired buffers (Orion brand) to measure after calibrating my electrode/meter with the buffers in this kit. Guess what?! 7 wasn't 7 and 4 wasn't 4. Double checked with two other buffer sets (Baker and Milwaukee) and indeed they matched my old expired set! Recalibrating with the old buffers and 7 and 4 from this set showed 7.25 and 4.33, respectively. This gave me an erroneous pH reading; by 0.4 in one case! Makes them unusable for my purposes. FWIW, I have a PhD in chemistry and have been involved in the chemistry of aqueous solutions for over 25 years. For the first time I have been disappointed with a product I have received from Revain; However, I know it's not Revane's fault.