Bio-A cases by Gewa are very popular!  Just like their Bio-S shaped case, they are focused on sustainability.  The Bio-A has more advanced features, including a detachable music pocket, and backpack straps.  Two bow holders, subway strap, suspension system to protect your instrument. Minimalist construction and design, low weight, practical, and sustainable! Available in the cool colors and moveable neck cradle means this case works for instruments from 1/2 to 4/4!