WARNING: THIS PRODUCT CONTAINS ONE OR MORE CHEMICALS KNOWN TO THE STATE OF CALIFORNIA TO CAUSE CANCER AND BIRTH DEFECTS OR OTHER REPRODUCTIVE HARM. WASH HANDS AFTER HANDLING. Course Thread Replacement HP Gas Cylinder Cap. Caps For High-Pressure Cylinder 80 Through 330 cubic Ft. Cap I.D. is 3 1/4. Threads: 7 per inch.