Black Diamond Equipment Centinal Flannel. charcoal color flanel buttonup Has herringbone pattern cloth with a cool reinforced button detail. in very good pre-owned condition. Our soft, organic cotton/hemp blend button-up that's the perfect layer whether you're granite slabbin' on a crisp day or cruising into town for a caffeine fix, the Sentinel Flannel Shirt is a supremely comfortable flannel with the style to match. This ultra-comfy herringbone pattern shirt features a classic button front with two chest pockets to keep your sunnies, passport and other essentials close while traveling.