LIAERBA CUTTER BLADE MTD YARD MAN GUTBORD FOR MOWER MODELS 50 MODEL - TECHNICAL SPECIFICATIONS LENGTH 438 mm CENTRAL BORE 10 mm EXTERNAL BORE 7.9 mm CENTRAL BORE INDEX 63.5 mm CODE: 13270317 ORIGINAL CODE 742-0171B , 742-0171 , 090.90.049 SR