I have been drooling over getting some ultralight camp shoes the last few years, reading every thread about the latest and greatest. I bought some Crocs, size large a couple years ago and wish they were lighter. Anyway, what I really wanted and had read about were Nike Mayfly running shoes, made of Tyvek. I had read a few years ago that a pair weighted around 4 oz. Man, I had to get some! Last weekend, surfing on the internet, I found mention that size 9 weighted around 5 oz. not exactly what I wanted to hear, so I thought a size 10 or 11 ought to weigh maybe 7-8 oz. at the most. Disappointed. I got home tonight and after finally making it inside, the first thing I did was open my box from Running Warehouse. I tried the Mayflies on and they fit, just barely, as it was suggested to buy 1/2 size up. I took them off and onto the scale they went. Big time disappointment, they weighted 11.1 oz., .2 oz. less than my large Crocs. Wah, wah! The good part, Running Warehouse has free return shipping. By the way, they cost $45.00 plus CA sales tax for us Kalifornians.