This part replaces the cap on the ends of bike handlebars, it's designed to press fit into the socket, however it may require some light sanding to get it to the right size.
This cap has a slot for some rolled up notes, i could fit £50 in tightly rolled notes inside.
I based the container on the English £20 note, which is quite a large note, so it should fit most paper currency.
The slot has some dovetails modelled into it, which allow a cap to slot on, the cap should be a fairly loose fit, however it won't be able to release once inside the handlebars, as it's prevented from moving more than a few mm by the handlebar walls.
If you like this model, please consider checking out my related designs:
Bike Handle Cap - Secret Key Compartment
I printed this using "Support - Everywhere", cap facing down, with a few interface layers and a Support Density of ~10%.
Support was easy enough to remove with an exacto knife, and left the part a perfect fit for my key.