I first bought a medium, then realized a small might be even better and tried that. And since I get annoyed by reviews that say "works great" or "too small" or "too big", I'm including photos to show you just what these guys hold -- and how they compare.First photo shows the medium size bag easily holding a medium-size charging block and USB-C card reader in the left top pockets, with 3' USB lightning cable and 3' Magsafe Apple charging cable in the left bottom pocket, plus a USB-C lightning cable, USB-C to USB-C cable, and USB to USB-C cable in the right pockets. Second photo shows the small size bag accommodating those same items in the respective pockets. Each photo shows both bags for comparison.Third photo shows the medium bag easily holding my memory disk holder in the big mesh pocket on the right and an empty pocket on the left (hey, I ran out of things to organize!) Fourth photo shows that I moved the disk holder to the right mesh pocket in the small bag because that bag's left pocket is unstretchable nylon instead of mesh and wouldn't hold the disk holder. I also took the opportunity to shift the 3' USB lightning cable to the large nylon pocket on the right because it was tight alongside the Magsafe cable in the small bag (photo two).Fifth photo shows the disk holder opened so you can see the memory cards for scale, and the sixth photo shows the two organizers side by side when closed. There's not a huge difference between them, but the small is less wide and long and thick If you want to carry what I carry, the small works fine; if you like longer cables, you might prefer the medium; and if you like longer yet, or bigger items, you might want the large.Hope this helps! I rate the organizers well made and organized, and my partner was impressed on our recent trip when her items failed and I was able to instantly produce a charging block that was faster than hers and a USB-C to USB-C cable that charged up her iPad where her cable had failed to conduct any juice.