Product Description : MUGEN SEIKI E0206 Differential Washer Set X6/X6T/M-Spec MUGC1206 This is a set of internal diff washers for the Mugen MBX5 family of buggies These washers are used inside the front, center and rear differentials and go behind the small internal gears inside the diffs These can wear out, it is a good idea to replace them when you replace the internal gears California Prop 65 Warning : This product can expose you to chemicals including arsenic, which is known to the State of California to cause cancer. For more information visit to the website.