Just got my new Jailbird device from Mature Metal.. After a couple of resizing due to my error in measuring.. it finally works well.. I will have to evaluate it and see if the gap works now that all the other sizes work too.. Tube length: 1.5 inches.. Tube diameter: 1.5 inches and gap: 1/4 inch.. Back ring was 1-7/8 inches Oval. I used this gap as it matches closely to my CB6000s.. but will have to see how it does since the Jailbird is much closer fitting.. Quality and service are excellent.. and comfortable.. but will let you know after a few days or weeks.. I don't have a local keyholder as of yet.. and play more on-line with long distance keholders or the timelock program for now.. so to add some fun to the game, I had Mature Metal add a second hole behind the main lock hole so that a numbered Key tag could be locked on as well.. just removing the "second hidden" key concern.... Add more to the accountability.. and fun.. 2 locks actually.. You can checkout the photos I added in my profile that show both metal locks and the numbered plastic lock.. Thanks MM..