The Step in accessory is a long platform for the back of the bike. It is either a footrest for the children seated at the back, or a deck for the bags. The Step in can be folded up without tools in a matter of seconds.
The accessory is only compatible with the gen2 frames. See the picture to identify whether your frame is gen1 or gen2. Heinzmann powered is always gen1, Shimano powered is always gen2, and Bafang powered can be either gen1 or gen2. New Bike43s are gen2. We may release a retrofit kit for gen1 frames.