SAFETY FIRST: Ensuring your child's safety is our top priority. That's why we've created a Kids Training Handle that is built with one-piece, heavy-duty Cro-Mo steel no welding involved. We recognize the significant force exerted when a bicycle falls, and our training handle is designed to effortlessly handle such situations with ease. Rest assured, your child will be in good hands with our reliable and sturdy handle. COMPATIBILITY: Compatible with round seatpost diameter: 22.2mm and 25.4mm with shim, 28.6mm without shim. However, it is crucial to ensure that the seatpost is securely positioned in the seat tube before installing the balanced handle.