These are for the OBDI connectors like in the Monte. My car no longer has a computer. Selling for $20 each plus actual shipping in the US.
One is a Alltest BrainMaster 3226 with the single GM OBDI connector. This one has the manual and has a display on the unit itself
The second one is a Sunpro scanner CP9001. Also has a manual and on this one you count the check engine light flashes and look up the code