The sleek, simple, and compact design allows the R90 to sit under your chair. It's inconspicuous & intuitive, and maintains your chair's size and turning circle. The V-Lock attachment system secures the R90 to most folding and rigid wheelchairs. The simple Control Box enables easy push-button use and can be ergonomically positioned for easy access. When power assist is not needed, simply push a button to raise the wheel up for zero rolling resistance. The Sunrise Intelligence app allows you to select the performance profile that best suits your environment.