I originally bought the Brixen Waterproof Low shoes. The web site said they ran 1/2 size small so I ordered the 1/2 size larger. But, they were loose on my foot so I returned them and bought the Brixen II Waterproof shoes. The web site said these also ran 1/2 size small so I ordered the 1/2 size larger. I bought these shoes for outdoor winter wear when it rains or light snow. They're great for being waterproof but they're narrow. They felt snug but reasonably comfortable compared to the Brixen. I wore them all day with thick winter socks and the next day my feet hurt for three days. I've never had that problem with any other Keen shoes before, and I probably own at least 15 pairs of Keen shoes (summer and winter styles). So, the next time I wore them I wore a lighter sock and the feet felt fine the next day. So, I'm a little disappointed that when its really cold out and I wear heavy socks, these won't be my shoe of choice.