We had purchased low pile chair mats at the store and needed high pile instead. When they came the sticker said high pile but they were the exact same chair mats as the low pile. They slide all over the place. Definitely not for high pile carpet.
Excellent hard floor chair mat. We purchased two (in different sizes) for our small office. The mats lay flat do not slide and are made of great material. I would recommend this purchase of Staples brand mats.
Only reason I didn't give it a higher number was that I think the "nubs" on the underside designed to keep the mat in place on the carpet they could be a bit smaller - when rolling across the mat on the desk chair you can feel the "nubs" and over time this is where the mat fails cracks and needs to be replaced.