The STIHL BASIC 9-blade set iscompatible with all STIHL iMOW® and iMOW® EVO robotic mowers equipped with the Disc-Cut systemWhen your STIHL iMOW® robotic mower drives over the lawn the Disc-Cut system equipped with 9.84'ovable BASIC blades guarantees you aimpeccable and reliable cutting resultThe rotating mowing deck ensures ahigh blade speedthat oneclean cutblades of grass. Regularly change the direction of rotation of the mowing deck and thus thesturdy and durable knivesalso contributes to a specific result. For optimal and lasting results we recommend:replace the blades regularlyat the latest after approximately 656.20 hours of use. Changing the blades is very easy. No tools are required. Always replace all 3 STIHL BASIC blades at the same time.