Pololu Basic Sumo Blade for Zumo Chassis is intended for use with the Zumo chassis and included as part of the assembled Zumo Robot for Arduino. It is made of 0.91mm (0.036″) -thick, laser-cut stainless steel, and it ships flat as shown in the product picture. The two tabs must be bent to an angle of approximately 70° before it can be mounted to the front of the Zumo chassis.
Warning: Do not try to bend the tabs after mounting the blade to the Zumo chassis as this could crack the chassis’ acrylic mounting plate or the mounting tabs themselves.
Pololu Web Site: https://www.pololu.com/product/1410