*PLUMBERSSTOCK EXPERT* responded:
Hi! Thank you for expressing interest in the Rain Bird 55K1 QCV key. The bottom part is not 1 inch in diameter. It is closer to 1-1/4 inches. Because this key has 1-inch threads. Brass pipes, like most pipes, has an interior dimension of 1 inch. If you can tell us more about what you will use it for, we may be able to help you better. If you're ready with your reply, feel free to post it on this page. You may also want to check this Rain Bird 5RC. That fits the bottom part of this QVC key. We hope this helps. Have a great day ahead!