pH Buffer Calibration Solution 3-Pack: pH 4.00 Buffer, pH 7.00 Buffer, and Electrode Storage Solution — 250 mL (8.4 fl oz) Each — NIST Traceable Reference Standards for All pH Meters

Great product. Will buy again. Accurate and high volume for the price.

I love it!

This is the dope. Love it!! Better than mixing powder. Always on hand Always ready. Except nothing less

These buffers are a bit more epensive than bargain brands, but you're paying for highly accurate pH calibration, traceable to standards. For a serious analytical or academic lab, using a high-end pH meter, this is value added at an excellent price. For your aquarium or hydroponic garden, and your pocket pH meter, it's not really necessary; go with the generic half-gallon jugs, or better yet, powder packets.

I use this product for calibrating pH pen. It works great. I put a small amount in a medicine cup and then follow directions for pH pen to calibrate. I highly recommend.

These standards are the same quality you’d expect from major lab suppliers. They work great for my bench top pH meter.

Great stuff. Love the print-out you get that tells the purchaser about the chemicals used and any hazards with them. Very professional. I will use nothing else for any PH pen.

Good value and works perfect for my meter. I like to test at 4 and 7 to be accurate. Would recommend!