I studied up for the best kit to add to my senior mother's favourite bike. She just needs a boost here and there, and security if her legs get wobbly.
I anticipated having to use some fabricating skills to get it running (some others have troubles with certain bikes) but not with the Roll. The only mod was taking off the clip for the PA sensor.
I took it for a test ride, played with the programming on the LED display, and have confidence that my mom will safely operate this unit for her specific needs. She does not want to go fast or accelerate quickly - although with wheel and power settings, this can be peppy (clocked 31km/hr into a mean north wind on the flat) for a 250W motor.
Communication with the company is choice...product shipped from Canada, way faster than expected considering my super remote location.
(I am not a bike savvy mechanic, tho a capable tinkerer, my concern was the tire size fitting the motor rim, from Nimbus tire on a 30mm to a 24mm on the 27.5 - it wasn't a problem)
This lightweight motor pedal assist (or throttle only) unit is perfect to maintain a safe and easy to secure bicycle for my mother to continue enjoying exercise and exploration of her area.