This is a green, Anchor Hocking, Colonial, aka Knife and Fork pattern, 3 oz. footed tumbler. This pattern was manufactured for only two years, between 1934 and 1936. This piece fluoresces when placed under a black light.
I have ten (10) of these tumblers available for sale, each one separately. Take a look at the pictures, and if you have questions, please e-mail.