I have several. Different brands, different widths. Most are 3/4" two are only 1/2 inch. The table (which is sometimes my ironing board), under the narrower wool mat always gets very wet.
The other thing I've noticed is that some brands are not as smooth on the top as others. I have 2 that have... sort of ridges on them. Like those potato chips. Or like a washboard. Yep. And I don't like to use them. If you get a chance to see them before you buy (can't do that with online purchases), you might want to watch for that.
overall, I really like using the wool mats-especially with my small travel iron-right beside my sewing machine.