What is the difference between M+S and the snowflake (3PMSF) symbol?
M+S (mud and snow) is a marking the manufacturer applies on its own, without a standardised winter performance test. The three-peak mountain snowflake (3PMSF, often called the Alpine symbol) means the tire passed a standardised snow traction test against a reference tire. A tire can carry both; for real winter use and in countries that require it, the snowflake is the marking that counts.