Rio Firefly 2.0

Battery-operated attachment with a handlebar that has two handles, two brakes, an accelerator, and a reverse lever. It attaches to the front of the manual wheelchair frame and can be removed by unclipping the front clamps.

I find the distribution of weight better across the arms when using this attachment, and it can be mostly operated with one hand, allowing you to do other things with your hands, such as having a drink. However, it is cumbersome.