This is an applicator for Squirt Chain Lube bicycle chain lubricant. It's designed with specially positioned internal channels that deliver the lube precisely where the parts of the chain meet.
Usage tip: clean the channels after each use (for example, by blowing through them) - otherwise, wax-based lube will harden inside, and you won't be able to use the applicator again.
The author marked this model as their own original creation.