In one embodiment, a coupler system for coupling a top drive and a tool, including a drive member of the top drive configured to transfer torque. The drive member having a housing with a bore therethrough and a window formed substantially laterally through the housing. An adapter of the tool is configured to be inserted through the window of the housing. In another embodiment, a method for coupling a top drive to a tool includes moving, the tool adjacent to the top drive, the tool including an adapter and the top drive including a housing having a window formed therethrough. The method also includes aligning the adapter with the window and inserting the adapter substantially laterally into the window of the housing, thereby longitudinally and torsionally coupling the top drive and the tool.