The bodhrÔan is an Irish frame drum ranging from 25 to 65 cm (10–26 in) in diameter, with most drums measuring 35–45 cm (14–18 in). The sides of the drum are 9–20 cm (3 1⁄2–8 in) deep. A goatskin head is tacked to one side (synthetic heads or other animal skins are sometimes used). The other side is open-ended for one hand to be placed against the inside of the drum head to control the pitch and timbre.