Nexen Roadian AT Pro RA8 All-Terrain Tires are comprised of a zig-zag sipe design and an open outside shoulder design that improves off-road performance with optimal mud extraction and heat reduction. This sipe-in-groove design prevents pebbles from getting stuck in the Roadian AT Pro RA8 tread and improves mud extraction performance. Nexen Roadian AT Pro RA8 All-Terrain Tires feature a multi-sequence tread design on the center and shoulder to deliver optimal noise, wear and drainage performance. All sizes are Three-Peak Mountain Snowflake certified (excludes OEM & Flotation).