This is a Bianchi wire lock. I think it's suitable for mini-velos and other bicycles with long seatposts. If the seatpost is long enough, it can also be attached to MTBs, road bikes, and cross bikes. If the seatpost diameter is thin, some kind of spacer may be required. A mount for attaching to the seatpost is included. You can remove the wire part by pressing the red button and sliding it. The red button's color had faded, so I repainted it, but that paint is also peeling. There are no functional problems. There is only one key.