The GPM B40OD100TK06 Spring Steel Button Head Flanged Washer Set is designed with precision-formed spring steel to provide repeatable seating and reliable support for button head fasteners. These washers help maintain clamping force under vibration and repeated assembly cycles, making them a practical upgrade for hobbyists focused on durability and consistent performance. Size specifications are 4mm inner diameter, 10mm outer diameter and 0.6mm thickness to match common RC hardware standards.