Rubbee is a Kickstarter project. It transforms almost any bicycle into an electric bike easily. It can be attached and detached easily. Put it simply, it is an electric drive for the wheel with a throttle to regulate the speed.
The Rubbee unit can be charged in 2 hours and you can see from the Kickstarter project, it can even be installed on a full suspension bike. Here is the video.
You can check out the video on full suspension bike on their Kickstarter page. I think what it did not show clearly in the video is the throttle. You will need to install the throttle first. It has quite a thick cable. Anyway, for Singapore, this Rubbee will not be approved by LTA as it uses a throttle. And the price is expensive (in my opinion).