We took the classic and fitted our twist fit system a dual directional ratcheting adjustment dialsize guidesmall 54 56cmextra small 52 54cmextra extra small 49 51cmextra extra extra small 47 49cmwe added a magnetic fid lock buckle to eliminate those pesky neck pinches and for ease of use with little fingersthen miniaturised it for the youngest of rippersshell durable and tough injection moulded abs acrylonitrile butadiene styreneliner high impact absorbing eps foam expanded polyst