Overall a great bag. As a hiker, I appreciate all the adjustable straps to get the best fit and all the organization. Plenty of room for my 10lb mini poodle and both our personal items for the day. He’s super comfortable in it. So much so that he’s reluctant to get out when it’s time. I think he’s right in the sweet spot for size with this bag. He can comfortably sit and look out the “window” and still enough room to curl up at the bottom to lay. A very tiny dog would likely get swallowed and much bigger would be uncomfortable. I do wish there was a bit more ventilation for hotter days and still be able to close the “window.” But that doesn’t keep us from enjoying our adventures in it.