DeWalt 285995-00 Washer For DW733 DW734 Planer Thicknesser

The part number 285995-00 is a genuine DeWalt external tooth washer used in various DeWalt power tools, most notably the DW733 and DW734 planers. 
Its primary use is to ensure a secure assembly of components within the power tool. The external teeth bite into the material it is fastened against, creating a locking action that resists loosening due to vibration or torque