I've finished a basic render of the PA tube design I've been working on. A nylon prototype should be arriving from the 3D printers in the new year. For this, I've had a custom security screw machined locally but there's no reason it couldn't be easily adapted fo a padlock or magic lock. The design's dimensions are easily customised and the device is fairly cost-effective for printing in stainless steel & titanium. Whaddya reckon?