The Nimbus Bearing Puller has been designed to slip onto any sized Unicycle bearing and hub configuration (with the exception of the Eclipse Hub) and remove the bearing with little effort. The Bearing puller cups around half of the bearing stopping it from slipping off while in use.
Bearings on unicycles generally last a long time; even when you take your unicycle in a fountain, or the sea, or just splashing around in the mud. They do give up in the end though; normally at the worst moment possible (the middle of a Polaris Challenge event for me). You hear them grinding first, then when you turn the wheel slowly by hand you can feel the restriction in the movement.