Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4697962.

A simple model of a cheerleader megaphone with handle. To make it a keychain, attach a small keyring to the handle.

This prints vertically with no supports.

If your printer supports changing colors at different layers, it can be printed in different colors. I used this to make the rings around the ends silver. You could also add a stripe to the body of the megaphone that way.