Iron Heart Heavyweight Flannels | UHF vs SHF | What's The Difference?

Do you know your Slubby from your Aspero? Here's Alex with a guide to this season's heavyweight flannels—including our traditional Ultra Heavy Flannel (UHF) and Slubby Heavy Flannel (SHF) shirts. Preview the full Iron Heart FW24 flannel collection here: https://tinyurl.com/4rhvwxjy Heavyweight and rugged, yet incredibly comfortable. It wouldn’t be an Iron Heart fall/winter collection without the UHF shirt, and FW24 offers more options than ever. For many years, our ultra-heavy flannels have been woven using Peruvian Aspero cotton, harvested from the foothills of the Andes mountain range. We then single-brush the face and double-brush the reverse of the fabric, creating the super-soft flannel that delivers the warmth and windproofing properties our UHFs are renowned for. As part of last year’s collection, we expanded the range with the debut of the first slubby heavy flannel shirts. Dubbed the ‘SHF’, these models use slub yarn cotton within their substantial 12oz weave. In contrast to the smooth Apsero cotton, this creates a much more irregular fabric hand with significant surface texture. Brimming with distinctive character and rustic charm, slubby flannels proved just as popular as their Aspero counterparts, with more patterns and colourways on offer this time around. Whether you choose a UHF or SHF, one thing remains the same though—an Iron Heart heavy flannel is a true winter essential.