Translation:Are you sure that that is the right power plug?
A plug is more general, which can, among other things, be an ignition plug, which would be "sytytystulppa" in Finnish, so just "plug" can also translate to "tulppa". "Pistoke" is exclusively a power plug. I don't think I've ever heard a USB plug being referred to as a "USB-tulppa". The only term that comes to mind is "USB-portti". A headphone jack can be referred to as a "jakkiliitin", "plugiliitin", and "plugi", or with the more general term "liitin".