This is a REMO hi-hat clutch. It has been used, so it shows signs of wear as seen in the photos. The bottom part is not a screw type, but simply snaps on, which made setting up the cymbals much faster and easier, and I found it very useful. Quoting from a musical instrument store website: Built-in spring. A new idea for a hi-hat clutch that frees you from the hassle of screwing with quick operation. Compared to models that use a regular screw, this hi-hat clutch employs a lock-notch system that allows for quick removal of the hi-hat cymbal. It also prevents the hi-hat cymbal from falling off during play. I'm selling it because I found it during a big cleaning.