I bought these for someone who wears braces and, thus, requires extremely large overshoes and boots. This is one of the very few boots sold that fits that requirement (size XXL and size XXXL).  Not only does the boot fit, it does well in snow and ice -- the boots are used many times a day to take a dog out and the snow has become very packed down and icy.  In the past we've had problems over time with boots developing leaks, but these seem well made.  Only time will tell, however.

The large opening is especially helpful to allow this overshoe to be pulled on over a very large shoe.