Bionx e-bike control cover

The Bionx e-bike control has a very smooth surface, which made it slip from my hands. In the end I ruined two of them. For the third one I made a cover, which allows to put the control into its holder together with the cover. 
I did not print it myself, at that time a colleague of mine had a 3d-printer and printed it with PLA. It fits quite tightly, probably because of the shrinkage of the material.