The head screws is made of stainless steel material, durable, strong and no rust. Forehead head screws is compatible with Ninebot ES1 ES2 ES4. Thread Diameter: 5mm, Head Diameter: 9mm, Total Length: 11mm, Allen Hex Drive: 3mm Easy to use, you can work well with these screw kits. Replace the old or damage part easily. 4x allen hex screws and 1x hexagonal wrench in package. Warning: It is illegal to ride electric scooters on public roads, pavements, or cycle paths. They are intended only for use on private land with the owner's permission. Thread Diameter 5mm Head Diameter 9mm Total Length 11mm Allen Hex Drive 3mm Material Stainless steel Type Head Screws Brand Unbranded/Generic MPN W2D94927368840 EAN 4894927368840 .