Quickly interchangeable frames allow you to switch from quad roller skates to inline and back with ease. The boots feature adjustable sizing for growing feet, and expand up to 3 sizes with the push of a button. With these versatile skates, you can enjoy all that skating has to offer. Switch out the frames by using 2 allen wrenches. Fits true to children's U.S. shoe sizes. Medium adjusts from size 3 to 6.