This is a vintage 10 oz. Dr. Swett's root beer bottle from the Desert Bottling Company Phoenix Arizona. It is a clear bottle with yellow and red paint.
Dr. George W. Swett's originally sold his root beer in packets and as a fountain drink in his pharmacies in the 1800's. He later shipped it to other pharmacies as a syrup to be mixed with soda water and later yet it was premixed and sold in bottles. Dr. Swett's Root Beer was sold up until the 1950's.
This bottle is dirty and has a lot of paint wear, but it is not chipped or broken. Once hand washed a bit it would make a nice addition to a collection. It measures 9.5" tall and 2.25" in diameter.