Purple Martin Gourds are a convenient and inexpensive way to create a habitat for purple martins. Group gourds in multiples to create an apartment complex. Made of plastic with drainage holes. Diameter of entrance is 2.25 in. and the size of gourd is approx. 6.5 inches long by 6.5 inches wide inside. Outside dimensions are approx. 6.75 inches diameter by 12.25 inches high. Gourd has a pre-drilled hole at the top for hanging.