Is the blade 4228 710 6051 Blade 600 mm / 24" the price for a single blade or two bladed ie the set?

These links are both for a pair of blades: Genuine: https://www.lsengineers.co.uk/catalog/product/view/id/24844 Non Gen replacement: https://www.lsengineers.co.uk/pair-of-hedge-trimmer-blades-500mm-for-stihl-hs45.html