Yes it’s kinda an expanding wedge thingy..
It’s definetly not a nut that digs into the inner of the carbon steerer tube, nope Sir’ee.
Think of it as an alloy 60mm in length cylinder shaped object that has grooves cut into it, then a nut that fits one end and a bolt that goes into the other (that the bolt would go through the cap) then the cylinder thingy is wrapped in a thin (very thin) alloy cover wrapping around the cylinder thingy. Then the whole assembly slides into the steerer and then as you tighten (un tighten) the bolt through the top cap the nut slides on the inside of this cylinder thingy up and down to tighten against the inner steerer tube.
If you understand that then well done, I’m not in the slightest mechanically minded and I managed it 😆
Ok, so I completely undid it and gave it a tap, like you would a SFN, and the nut just dropped out the bottom of this cyclinder thingy into the bottom of the steerer, where upon it had to tip the bike upside down to get it to locate back in the base of the steerer then attach the bolt in back into it to get the nut located back into the cyclinder thingy where the location grooves are.. Bit of a pain.
So had I known that the whole assembly comes out in one affair you just undo the bolt a few times then lift the whole thing out in one as you raise the stem/bars off I’da been done in 20mins, as is it took me about an hours but hey.
Reason I posted is because it’s the first time I’ve seen this assembly before. Certainly neater than an SFN digging into the carbon steerer IMO.
Nope no gloves, not outdoors, good old hacksaw with me blowing the carbon dust all over my spare bedroom.
😀