I honestly love these boots! I'm an Angus rancher in SW Montana and with winter setting in decided to pick up a pair from a local retailer. I've never experienced anything like these boots as my feet stay warm and comfortable all day... the temperature is hovering around freezing currently and after being out in the feedlot and doing miscellaneous chores around the ranch, my feet are still dry and warm... there's plenty of insulation and the tighter fitting tops are snug around my calves, trapping a lot of heat in. You can roll the tops down if you get too warm. The build quality is very good and while insulated, feel lighter than my irrigation boots! I wear a size 12 and the fit is perfect. I don't need to wear multiple pairs or thermal socks.