7/8″ lower opening, 9/16″ upper opening.Fits Ford/New Holland models 1801 Indust/Const, 1821 Indust/Const, 1841 Indust/Const, 2030 Compact Tractor, 2031, 2111, 2131, 2150, 2300, 2310, 2N, 3000, 3100, 3110, 3120, 3150, 3190, 3300, 3310, 3330, 340, 3400, 340A, 340B, 3500, 3550 Indust/Const, 4030, 4031, 4040, 4110, 4130, 4131, 4140, 420 Indust/Const, 445 Indust/Const, 445A Indust/Const, 450 Indust/Const, 4500 Indust/Const, 501, 535 Indust/Const, 540 Indust/Const, 540A Indust/Const, 540B Indust/Const, 541, 545 Indust/Const, 545A Indust/Const, 550 Indust/Const, 555 Indust/Const, 555A Indust/Const, 600, 601, 620, 621, 630, 631, 640, 641, 650, 651, 661, 700, 701, 740 Indust/Const, 741, 800, 801, 820, 821, 840, 841, 850, 851, 860, 861, 8900, 8N, 901, 941, 950, 951, 960, 961, 9N, Golden Jubilee, Jubilee, NAA, NABReplaces 8N7277 C0NN7277 C5NN7277C