Thank you for viewing. This is a set of "Bigsby B5 Spacer" and "Arm Spacer". When you install the Bigsby B5 Spacer, the angle of the arm will also change, so using the Arm Spacer for fine adjustments will make it more comfortable to use. Please note that it cannot be installed on the B50, B500, etc. of the Lightning series. Please check the individual product pages for detailed explanations of each product. Thank you for your consideration.