Screw in bump stop and screw. NOT CHEAP 3D PRINTED. Diameter at base is 15mm. Diameter at top is 12.5mm. Height is 9mm. Screw length is 15mm. Will be despatched within 4 working hours of receiving cleared payment. No questions asked, hassle free refund if unwanted or ordered incorrectly (you pay return postage costs). Default postage is Royal Mail Large Letter Second Class. I charge what Royal Mail Charges me (plus the 13% that eBay charges me for selling the postage). If you want the item quicker you can select first class postage at an extra cost. No additional postage charges if more than one item is ordered.