1.3mm pushrod connectors fit for steel wire with diameter of 1.0-1.3mm. 1.8mm pushrod connectors fit for steel wire with diameter of 1.5-1.8mm. 2.1mm pushrod connectors fit for steel wire with diameter of 1.8-2.0mm. The distance between the servo and the pushrod can be adjusted quickly and fixed firmly by these pushrod connectors. Ideal DIY accessories for RC model airplanes, model car, RC helicopter, etc. Made of metal material, durable and sturdy, can be used for a long time. Package includes 20pcs RC aircraft push rod connecting rod adjusters. Hole Diameter 1.3mm/1.8mm/2.1mm (Choose the hole diameter you need) Material Metal Colour Silver Brand Unbranded/Generic MPN TJ4894832057983 .