Review on General Tools PH501 Digital Pocket by Justin Hollins

I've used a lot of PH pens over the years, most of which are between $20 and $100 new. Cheap ones have to be constantly recalibrated and are then usually unusable within a few months. The expensive pens I had were in no way superior to this $50 pen. For the money this is the best pen I have ever used. I've had it for about 6 months and it stays calibrated for a long time - and easily and accurately recalibrates itself when needed (rarely more than 0.2 drift). Many more expensive pens have replaceable electrodes - and I don't. I don't know if the electrode of this pen can be replaced. However, with the expensive pens I had, replacing the electrode didn't make economic sense. Once the electrode is removed, you can spend a few more dollars on a brand new pen that will give you a new warranty. A guarantee is good for a PH pen because they tend to be very picky. UPDATE: I bought this pen in May 2010 and he just passed away on December 4th 2010. I know PH handles and how fragile they are and I treated this thing like a kid. It is washed, stored properly with storage solution in the lid and handled with the utmost care and dies after 6 months. I will update this update with another update - once I see how General Tools handles the warranty/replacement. The pen worked great, but based on how I've used and handled it, it should last at least a couple of years.