These cap squares are 2” wide, 7 ¼” in length and fit 2” trunions. They fit over the trunions to hold barrel in place on carriage. Specifically manufactured for the CB0630 1841 6-Pdr. Cannon barrel, with some fitting they can be made to fit the MC0607 Coehorn and the MC0606 ½ Scale Napoleon. Caps will not fit MC0627, CB0605, or MC0629. Sold in pairs.