This transition bag is the bees knees! Very roomy for all of my triathlon gear. This morning I had to park a mile away from the start of the race. I was able to throw the bag on my back and ride to the race.It also sits upright unassisted. Has 2 mesh pockets inside big opening. I used it for my running cap, heart rate monitor, watch, and quad lock armband for my phone.One mesh pocket on both side of bag for water bottles. Bag is well made with thick material. Waterproof bottom section for wet suit or wet shoes, or great for keeping sweaty clothes contained.Small pocket on top for keys, wallet, and other essentials.Clip on front for helmet, or the big section will fit helmet and shoes easily with even room for a towel.Update: still a great bag. However, the other day I threw my tri suit in there after a swim. I had a short drive home and had nothing else in the bag so I left in on my back for the drive home. I felt the water seeping through the waterproof section and on to my back. That being said, I have never had an issue with water seeping through if I'm not pressing it, which 99% of the time is the case. I still love the bag.