Hi Krista, thank you for your question! Both are good choices. Our warmest boots at Altitude Sports are usually the ones with the 400g insulation. You can shop brands like Baffin (probably the warmest ones we have, used by people who stay outside for hours like crossing guards), Sorel or Kamik, who offer the biggest selection of very warm boots. One thing to consider is also how soft the lining will feel against your feet. I know many people with Raynaud’s Syndrome do prefer UGG boots for that reason, for they are very comfortable and also very warm. Another thing to keep in mind is that the heat not only comes from your boots, but also from your socks. I’d recommend merino wool socks, like those from Smartwool or icebreaker!

thank you for that clarification. I’ve asked reps from timberland, blundstone, and a buyer from a major retailer, and nobody knew.