This adapter works with the Axial 2 speed servo saver kits, the adapter has a micro 25T spline to fit our RS100 Micro Servo. Our adapter replaces the spline mount portion, and you use the rest of the Axial saver kit. Our kit includes our printed Adapter, one M2 x 10mm screw, and washer. Works with Axial Parts Ax31009, AXI252025, and other similar parts. The adapter is a very snug press fit to ensure proper engagement with the micro spline.