injector test light type?

i need to buy some injector testing lights..... i find my 2600i listed as mfi/pmfi.... which light do i use...i havent bought them yet and would like to know before i buy them....thanx for the help

I personally have no experience with injector test lights, but have used a mechanic's stethoscope in the past to put my ear on the injector and hear it physically clicking. Cheap purchase from harbor freight.