Dear Jan,
When I purchase new needles they all have two numbers on them. Why? -Anonymous

Dear Anonymous,
Most single shaft needles have two numbers on them, such as 75/11. The first number is the diameter of the needle shaft, which is the European system for sizing needles. The second number is the American system for sizing needles based on an arbitrary number. In both systems, the larger the number the larger the shaft and eye of the needle.