1-1/8" bolt thread dimensions. Head to end of bolt 3-1/2". Under Head to end of bolt 3.00" Thickness of head: 1/2". Mower blade: 1-1/8" national fine thread. Includes bolt & nut. This bolt kit is not only made for the Bush Hog 3615 rotary cutter, but fits the Bush Hog 3615, 3209, 3210, 3368, 2610, 2615, 3610, 2415, 2315, 286, RZ60, 126, 160, 166, 2010, 2512, 268, 310, 502, 109, 305, 306, 315, 1050R, 12, 1206R, 1207R, 600, 105, 1109, 1126, 1209, 1226, 307, 3008, 1310, 1315, 1600, 205 & More. Replacement Kit for Brown, Bush Hog, Darrell Harp (Big Bee) HD, HICO (Howse), King Kutter, Long Mfg & Lowry. Kits includes bolt, lock-washer & jam nut.