I have these two.

Allprettyall Digital PH Meter PH Tester

Lol WTF all pretty all?

Apera Instruments AI311 Premium Series PH60

The allprettyall works fine after 2 years of not caring for it properly. I leave it out, uncovered, don't clean it..just treat it like crap and it's always within .02.

It's a gamble and if you don't have a second and third method of checking, then probably don't get it.

The apera one I got has replaceable probes. 3 different types of probes, for liquid, semisolid, and something else.. I Forget.

I have 2 tips for liquid, one for garden, one for pool maintenance.