pihwht

Yes. The threaded collar is supposed to reduce wobble/free play in the part of the seat post which actually attaches to the bicycle seat. There's a square metal bar coming down from the seat to the collar. Loosened the collar reveals a round plastic sleeve which sticks out of round part of the seat post which goes into the bicycle frame. As part of the collar there are four wedges which push into the round plastic sleeve or grommet. Don't seem to be able to push them in far enough for the threads to engage. Of course, once it is pushed, turning the collar is a trick anyway. The threads are very fine.