Flax vs non-flax spinning wheel

What is the difference between a flax and a wool spinning wheel.

Major difference is a flax wheel will have a distaff and the oriface is much smaller.

All types of fiber (flax, silk, wool) can be spun on any wheel.

Thank you. I could not see a design difference in the pictures and was confused why some were called flax wheels. My assumption was something to do with the orifice but couldn’t get close enough to a pair with my calibers.