I recently got a new chair, I weigh around 235, and have a higher-end (near $100) acrylic chair mat on top of short carpet. I wanted casters that were quieter and moved much easier. I tried the single rollerblade-style caster, but the rounded profile only created a deeper depression in the mat, and was even harder to get moving again. On hardwood or tile (or a tempered glass mat), that type may work, but not for my situation, so quickly refunded. Then I found and tried these, and am still wondering why they don't have tons more excellent reviews.. They're perfectly sized (3"). They change direction easily. They start moving easily and they're smooth and quiet. They're much nicer looking and perform way better than the garbage 2" plastic dual wheels that usually come as standard. Yep, they're worth the extra! Upgrade NOW! Highly recommended! Additionally: I also added these to the tall stool I use in my optical lab. They are completely smooth and totally quiet when transitioning from the linoleum floor to the rubber mats with the diamond-plate pattern. Being 3" and having the softer tire tread makes all the difference in the world. The plastic 2" wheels were difficult to move around, and rattled constantly. I'm even more impressed now at just how much better these are than the complete garbage standard 2" plastic casters. Do not hesitate to buy these! And no, I have not been compensated in any way for this review. I will immediately swap the casters to these for any and all future office chair purchases because they really are that good! :-)