Rotorland ZMR250 Quadcopter Arm Spacer Kit (4 pieces) Black Pack of 4 custom 3D printed arm spacers for ZMR250 quadcopters Printed in black PETG plastic - strong, heat resistant and non-toxic Smooth beveling on both sides for non-abrasive wire routing Slightly smaller on the back side (interior side) than other designs to give you more room Custom designed by Rotorland