uxcell 100Pcs Black Rubber O Ring 20mm x 14mm x 3mm for RC Plane Prop Saver Country of Manufacture: CHINA; Brand: Assisi Material: Rubber; Net Weight: 51g Package Content: 100(+/-2%)pcs x Prop Saver O Ring; Main Color: Black Outside Diameter: 20 mm / 0.787"; Inside Diameter: 14 mm / 0.55" Thickness: 3 mm / 0.118"