Parker Hannifin 63NTA-6 Stainless Steel Air Brake-NTA Insert for 3/8" Tube: Amazon.com: Industrial & Scientific
Metal Threaded Star Type Insert for 1" OD Round Tubing - Threaded Tubing Inserts Threaded Tube Inserts Round Tubing Inserts Chair Leg Threaded Star Tube Insert Threaded Inserts 3/8-16 (4): Amazon.com: Industrial
1 1/4-12 Heavy Wall Right Hand Thread Tube Insert for 1 1/2 ID Tubing – Barnes 4WD