Whats this for?


I bought a Mark Levinson 326S here and was looking over the owners manual box contents and I read "1/8-inch hex key". What the heck would an allen key come with a preamp for? While I don’t have the preamp in possession right now to look at screws. Would Madrigal/Harmon want you to remove the bottom of the unit for some reason, what reason? Or is it the feet that you can change?
2020matters
My Belles Aria integrated has a tiny screw that fastens the volume knob to the thing-y that turns (sorry for the lack of precision). It is tightened by a tiny key. 
I did an owners Manual search and only found Hex key in "box contents". I've attempted to mail Levinson already and its been a week and no reply. So, not sure that worked out, I'll try again.