An outdoor surface treating apparatus having a body having a handle and a head arranged to be removably connected with an accessory tool assembly. The head includes a first engagement arrangement for releasably engaging with a second engagement arrangement in the accessory tool assembly. A drive unit, arranged in the head, includes a first coupling member for drivingly coupling with a second coupling member in the accessory tool assembly. The first engagement arrangement is fixed. The second engagement arrangement is movable between an extended position and a retracted position. The accessory tool assembly includes a biasing element for biasing the second engagement arrangement into the extended position. As the accessory tool assembly is aligned with the head, in particular when the first engagement arrangement is aligned with the second engagement arrangement, and is moved along a movement axis into engagement with the head, the second engagement arrangement first moves over the first engagement arrangement against the bias then returns to the extended position and locks with the first engagement arrangement while the first coupling member couples with the second coupling member.
