Mounting Button for Steel Spacers Würth Elektronik Mounting Button for Steel Spacers offers a fast, tool-free mounting design, PA66 construction, and a 1 to 2mm panel thickness. The WA-EXRV series features a screwless connection, saving time and allowing fast mounting during mass production. Würth Elektronik Mounting Button for Steel Spacers features a UL 94V-0 flammability rating and a -30°C to +85°C operating temperature range.