Pill shaped storage box with screw cap

This is universal storage box that I've designed originally to protect or some sensitive pressure transducers during transport.

The box has an ID of 32mm and an internal length of 84mm.
Both the box and the lid have a 5mm hole to attach a leash.
The cap is screwed onto the box.
 

For making the box water proof, place an Oring behind the end of the thread.
O-Ring cross section diameter should be between 1.78 and 2 mm to seal of the threaded connection.