I got this interesting set of pieces for my Drive Poly-Fly Wheelchair. And I am adding them to my arm-rests, with them being forwards and their sides still on, because they are my first and most trusted "carriers". ;) The Good stuff, that cup-holder makes a fine, flexible "bumper", it is very durable work. And it just "barely" fits my favorite mug and it seems to "cling" a bit, to the bottom, and that could be an interesting "hidden benefit"? ;) (BTW, what size is that cup-holder nut? I'd like to try something to improve rotating it, more freely around an arm-rest's bar.) Here's an obvious "benefit", those two big and smooth openings provide a pretty decent large "hook shape" that holds the handles of a plastic bag to carry some of my stuff or a small but hot TV dinner. ;) *** AND has anyone ever thought of making special mugs for this work? Something with a safety-top for incline problems, possible spills and HOT STUFF protection might be EXCELLENT!!! *** The upper "clamp" cane-piece snaps onto my fold-able cane, nice and solid. But it takes a bit of force to clamp it onto the larger upper-section of my offset cane. (I hope, I don't break it. :( But thanks for those rubber pieces. One of those does help to lock your clamp onto a slightly curved section, fairly nicely. ) ((( So, for now, I have the cane-clamp above my side-plate and the cane Velcro-strap above that as a needed "safety piece" for more needed street-security? (btw I used 2 of those large sizing-pieces fastened tightly within the clamp, so I can swivel it away from my seat. The strap swivels naturally enough.) *** To Medline, the strap could use about four or more inches of Velcro to increase safety. And adding a snap to it, that snaps onto a special double-sided female-coupling, replacing the current one of course, might be some of the BEST SECURITY that I can think of? ;) *** And the cane's base piece is under the metal foot-rest piece and since it is offset to the inside, from the rest, I left it to free-spin, so i can still use it, for adjustments and hide it.))) BTW, those two cane-pieces, the lower "base" and that upper "clamp", will rotate 90-degees on their axis, when you pull them out, a little. And another missing detail in Amazon's pictures, is a 12-point star pattern for the cup-holder's bolt to rotate and lock into, when it is all tighten.