Trying to revive an old hard drive I had a few old backup drives from my Windows computer that I wanted to go through. They are 5-6 years old. And they are internal drives so I got a USB adapter kit from the brand Deltaco.

So far I haven't been able to get one of the drives to show up in Finder.

So my question is, if these drives haven't been broken by the years what is the best way to see if I can extract some info from them?

Is there any special extraction software I need or is it of no use if the drive can't be found in Finder?

Any other tips?

Appreciate all the help I can get in this matter!
Did you go into Disk Utility to detect the drives?  Normally they would show up there although they'll need to be formatted in a Mac Journaled format or Windows ExFat one.  If you cannot see them in Disk Utility you may need to connect them to a Windows machine and do a format there. Hopefully not necessary and Disk Utility will sort you out ;-)