2-1/16 in (5.2 cm) base. Fits most No. 4 size drip coffee makers. Made with 100% biodegradable fibers. No chlorine bleach used to make this product. In season year round. Our Story: We believe in pairing the simple goodness of nature with products that really get the job done, and delivering that quality to your neighborhood grocer. With Full Circle Market, better choices and affordable prices are always in season year round. Come visit us! FullCircleFoods.com is your destination for unique recipes, interesting articles, product overviews and more. www.fullcirclefoods.com. Quality Guaranteed: If for any reason you're not satisfied, we'll give you a full refund.