so does anybody have some tips for mailing small electronics to countries outside the US?

https://www.tindie.com/shops/rezahussain/arduino-ph-shield-by-dormant-labs/

is a good one too. You should google 'omega engineering' they have ph probes that have threads so you can screw them into things. They also have fittings to help mount them.

Drew I don't know if I am too late, but I have recently released a ph shield for arduino on tindie. I'll be writing a in depth tutorial on how to control ph in the few weeks too.