Countax OEM Replacement Blade 305-0909 
FITS MODELS: 169381300, IBS machines with 50'' (1.26m) mowing deck; Left hand blade 
Lenght 19 1/16'' (484mm)
3/8'' (10.2mm)
Central Bore 5/32 x 5/16'' (4mm x 8.5mm)
1 3/4 x 1 13/16'' (44.5mm x 46.5mm)
Pitch Centre 2 15/32'' (62.8mm) 
5/32'' (4mm)