A torque transfer coupler for a roller blind. The torque transfer coupler has a central body securable to an electric motor and includes one or more torque transfer elements engaging the interior of the blind's roller tube. The coupler includes an anti-slip member having one or more resilient portions having a rest position and a deflected position. When, in their rest positions the resilient portions have a dimension larger than the cross sectional area of the roller tube. When in their deflected positions and received within the roller tube the resilient portions engage the interior surface of the roller tube resisting the withdrawal of the torque transfer coupler, and the electric motor secured thereto, from the interior of the roller tube.