12pcs 35mm Inner Dia PE Plastic End Cap Bolt Thread Protector Tube Cover Blue | eBay
34pcs Black Pipe Post Bolt Screw Rubber Thread Protector Cover Vinyl Tube End Caps,Assorted 1/4-inch to 7/8-inch-5 Sizes : Amazon.co.uk: Business, Industry & Science
Plastic protection cap for 30mm tube (5pcs) - Carbonwebshop