A covering for an architectural opening is provided. The covering may include a roller rotatable about a longitudinal axis, a shade associated with the roller, and an operating system operably associated with the roller. The operating system may include a base, a drive mechanism, a transmission, an actuator arm, and an engagement arm. The drive mechanism may be associated with the base to provide an input torque. The transmission may be associated with the drive mechanism to selectively transmit the input torque to the roller. The actuator arm may be associated with the base to indirectly set a rotation direction of the roller. The engagement arm may be associated with the base and engageable with the transmission.