Rubber well nut commonly used on the FJR to fit the screen to the upper fairing and leg shields to the early FJR1300's. Its a captive threaded  metal portion held in a rubber sleeve . When the screw is inserted and tightened the rubber portion pulls up against the fairing and secures the part by grip. Yamaha OEM well nuts cost £4.20. These pattern ones less than half the price.
Lubricate thread of fastener when using well nut and no need to overtighten.