HONDA ROTARY MOWER KNIFE BLADE FOR MOWER ROTARY MOWER FOR MODELS HT3813K0 , HT3810K1 MODEL - TECHNICAL SPECIFICATIONS LENGTH 490 mm CENTRAL BORE 21 mm OUTER BORE 10.5 mm CENTRAL BORE INDEX 88 mm CODE: 1320232 ORIGINAL CODE: 72513-750-305 , 72513-750-010 SR