Lamy M22 Ballpoint Pen Refill - 0.5 mm Fine Point - Blue

I’ve gone through two of the M22 refills in the broad tip, and both have been excellent. It is not quite as smooth at the Monteverde “Soft Roll” refills for the M16, but still pretty close. I am pretty sure the M22 uses the same ballpoint ink as the larger Lamy M16, but for some reason the M22 seems to write a lot better.

Does anyone know what size the tip is?