Wide Compatibility: This adjustable height stand works with the 21-inch Echo Show 21 and 15-inch Echo Show 15 smart display (Device is not included) Easy Screw Assembly: The show 21 holder stand consists of a round base and a support rod. Use a screwdriver to fasten the two screws into the designated holes, ensuring a stable stand connection that provides reliable support for your show smart device Non-Slip Base for Extra Stability: The riser stand features a non-slip base that keeps your show 21 and show 15 (1st and 2nd generations) securely in place. This design prevents slipping or desk scratches, during height or angle adjustments Raising and Lowering Capability: This aluminum mount stand for show 21 and show 15 features a rotating locking mechanism that lets you adjust the height, offering flexible elevation for an ideal viewing angle. Up to 9.1 inches Enhanced Viewing Flexibility: Designed for show 21 and show 15 (all generations) stand offers a 90-degree tilt and 360-degree swivel, allowing you to adjust the angle for optimal screen visibility, sound clarity, and a personalized viewing experience.