Here is an AE Swede 3D printed barrel band. These are printed using a carbon fiber reinforced filament and offers exceptional strength while retaining flexibility so its not brittle. These fit both carbon fiber .5 L bottle and aluminum .45 and .5L bottles. There are double clamping screws and a wide band to really get a hold on the shroud and tank to help lower the risk of the barrel getting knocked out of true.
Double them up for superior ability to hold true when bumped.