https://alexnld.com/product/20pcs-metal-rotatable-bearing-for-diy-crystal-jewelry-nail-art-decorations-4x5x2-5mm/?hilite="2 PCS White Fuel Tank Fittings D4.5mm Oil Pipe Stopper Aluminum Metal Tube Plug for DIY RC Gasoline Jet Boats 3-4mm Tubing Parts"