100PCS X CNC Aluminum alloy elastic Shaft Flexible coupling winding couplers encoder Z Axis 4MM 5MM 6MM 6.35MM 8MM 10mm *FD557-565 Product Description Aluminum alloy elastic Shaft Flexible coupling winding couplers encoder 4/5/6/6.35/8/10mm Suitable for model shaft connection Easy to install, buffer, shock absorption, abrasion resistance Features Material: Aluminum Alloy(Oxidation medication on Surface) Model 4MM 5MM 6MM 6.35MM 8MM 10MM 90 degree with 4 Screw holes Size:Diameter*Length=18*25mm Model: e.g. 5mm To 8mm One hole=5mm Another side=8mm Note:Because the point "."of 6.35 isn't allowed within the selection,so that "0" means"." It is suggests that in order for you 6.35mm TO 6.35mm,pleaes choose the"6035mm To 6035mm" Package 100PCS X Coupler 400PCS X Screw 10PCS X Wrench Size and quantity,depends on you. (if you wish varied side,we can choose up each of them.Choose what you need)