Three-Peak Mountain Snowflake tires or 3PMSF tires are those that utilize a rubber compound that retains flexibility and traction in cold temperatures.
The 3PMSF symbol or icon, which appears as a snowflake inside the outline of a three-peaked mountain, often sits next to the letters M+S (Mud and Snow rated) on a tire’s sidewall. While not every all-season tire is designed for severe winter driving conditions, the 3PMSF designation found on some of them means you will have more grip than a standard all-season tire. The U.S. Tire Manufacturers Association (USTMA) established specific tests to qualify for the 3PMSF designation. Since 1999, manufacturers have met and exceeded those requirements, making today’s tires some of the safest and best designed on the road.