Years ago I posted a picture of a handy oiler that looked a lot of what you have, but it was just a 4 or five inched long. Possibly someone what is better in looking up old things on this site can find the picture I posted.
I am not going out on the limb with suggesting what it is, but, too long to be a handy oiler, too short to be a railroad oiler.
Author, Gas Pump Identfication books 1st & 2nd Editions & Air Meter Identification books
We rebuild ECO air meters and sell parts.