The diameter of the hole is 1.8mm, fit for steel wire with diameter of 1.5-1.8mm. 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 1.8mm Material Metal Colour Silver Brand Unbranded/Generic MPN MEM95243267527 EAN 4895243267527 .