The Alberta Boot has 200g of insulation and a removable felt lining. Most boots only have one or the other, but the Alberta has both. That makes it one of the warmest men's winter boots; in fact, it's cold-rated down to -40F. The other thing that's great about the felt lining is that it pulls out. That means if you accidentally get snow down inside, you can pull out the liner for a faster dry. Durable exterior materials provide long-lasting wear, and a rubber sole gives sure footing.