The bohrán (pronounced /ˈbɔːrɑːn/ or /ˈbaʊrɑːn/; plural bodhráns or bodhráin) is an Irish frame drum ranging from 25 to 65cm (10" to 26") in diameter, with most drums measuring 35 to 45cm (14" to 18"). The sides of the drum are 9 to 20cm (3½" to 8") deep. A goatskin head is tacked to one side (although nowadays, synthetic heads, or new materials like kangaroo skin, 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. One or two crossbars, sometimes removable, may be inside the frame, but this is increasingly rare on professional instruments. Some professional modern bodhrán integrate mechanical tuning systems similar to those used on drums found in drum kits.