Interior Gauges

Alright im posting this again because I cant find the first thread i typed on this. Okay tomorrow im gonna go get a oil pressure gauge, now the pods that they sell for those do they make them for certain cars, or is it one pod fits all? Also I know that it comes with directions but i might as well ask people who have put gauges in their car. What tools do i need and what do i need to do to hoke up the gauge? Thanks