I'm glad I followed Tuki's urgentment that I provide measurements for my J10C. Jessie (the builder) indicated that the J10 and J20 are the same dimensions; however, there were slight differences that would have made a bit impact, i.e., differences in the width and placement of the handles (my J10LC's handle is not as wide as that indicated for the J20; and is also placed a bit off from that listed for the J20. So, I'm glad I submitted as Jessie does make these by hand. The bag's padding remains incredibley dense; outer material extremely robust; and the shape, assuming you provided accurate measurements -- fit perfectly snug (not sloppy, louse, or really tight. I chose the slip on as my amp does not often move, I needing a slip on cover when not in use (though in use almost every day). I have 5 other Tuki covers purchased 10+ years ago (?; for 2 1x12s, Dr Z Rt 66 and Z-Verb, and an Aracom attenuator); these covers have fully retained their utility in providing protection -- though, I am lucky that I have been able to find the velcro straps that latch the bag from the bottom to each of the larger bags. The bag for the Aracom is sort of a masterpiece -- providing protection for that unit's knobs and connectors with a shape made difficult because of that unit's guards on one side -- not the side with the control knobs. So, to me, the Tuki cover for this is an absolute must have. If you think you need -- don't hesitate -- these are outstanding products.
