Blade for lawn tractor mower mower 476 487 490 494 496 497 498 720 760 Columbia 51 REK51 A: 508mm B: 10mm C: 8mm D: 63.5mm E: 4mm F: 50mm A: diagonal blade length B: centre hole dia. C: positioning hole dia. D: positioning hole dia. E: blade thickness F: blade width MTD Code: R301019 Original code: 7420123 320003484 AT