PSI meter for RO/DI system

[Snufflupagus]

Hello all,

Wondering if anyone has a diy psi meter, and would help me out on what I would need to hook it up to my ro/di system. Note I really just need to know what kind of psi meter I need to pick up and where to get them at, the hose hook-up part can't be that difficult, though any tips are always welcome.

Thanks,

Colin