Dog Gone Smart's Nano Knit Sweater is the perfect combination of style and function. Our Repeliz-It Stay Clean Nano protection, which repels dirt, stains, odors, bacteria and fungi. The Nano Knit has a new Ultra-soft Nanosude collar with a cozy knit fabric that are both highly durable and double lined to provide extra warmth. Temperature Rating: 50 degrees F (cooler), 30 degrees (lower limit), 0 degrees F (extreme).