UPDATE: I'm changing my 1-star review to 4-stars. After leaving my review I was contacted by the company and sent 2 new mats that are supposed to be their updated product. The plastic is much thicker and more stiff. My wife has been using one at her desk for the past few months and it has been holding up well so far. The new mat is definitely higher quality than what I originally received. I am still dropping a star for my experience with the original product (x2), but the company has made it right and I can only hope that all future orders will receive this updated mat.

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I guess these work if you never sit in your chair? I bought 2 of these for my home office 10 months ago, one for my wife and one for myself. My wife doesn't spend much time at her desk, so the mat doesn't see heavy use. Hers is still in relatively good condition sans a few marks from the chair wheels.

On the other hand, I spend a lot of time at my desk. Within the first month or two, the edges started to pull up so anytime I move the chair a little too far and it goes off the mat it gets stuck and I have to lift the chair up to get it back on the mat. Now, 10 months in the mat is covered in white lines from my chair and has giant cracks in several places. The edges have lifted up even more.

Definitely look elsewhere for a better quality mat.

Update:
Almost a year after buying this i wrote my original review. Shortly after, the seller reached out to me and offered to replace the mat i had originally purchased with a new one.

The new one lays flat from the moment i opened the package. It's also clear rather than translucent which I like. Basically all the complaints I had in my previous review have been addressed.

What more can i say, it works great and i recommend this item and company.

Old review:
Pros:
My Carpet is protected.

Cons:
I have had this for over a year now, and the edges STILL don't lay flat. I can't tell you the number of times that me or my girlfriend have accidentally kicked it with our bare feet due to the lifted edges.
Doesn't stay in place, I think this is because the protector doesn't lie flat so it's not touching the ground enough to hold.
If I accidentally roll off of the protector, I have to stand up and lift the chair back on due to the lifted edges. This becomes extremely frustrating very quickly.
(See pictures)

Misc:
This isn't their fault so I'm not counting it against them, but be sure to measure your chair, I ordered the smallest size thinking it would work. While it fits, it is a little narrow and my chair keeps rolling off of it.
Summary:

I do not recommend this. I gave it a year to lie flat, but it still hasn't.

[UPDATE - May 10, 2017]
I have modified my original review from 2 stars to 4 stars.
The main reason is due to the excellent customer service which I feel should be recognized.
The company contacted me via email regarding my poor experience with their product and offered to make it right by sending me a replacement mat.

The newer mat is different (it is clear instead of the opaque white of the original) but I'm updating the review because good customer service is so important and so rare.

[ORIGINAL REVIEW]
Cons:
It's been only a little over two months and the product is not holding up well. I'm not a very large man and I'm using an average plain office chair with wheels. All sides are curling up. The corners are curled up even more, between 2 - 3 inches. It's getting annoying stubbing my toes constantly. And if the chair rolls off of the side, you have to get up and lift the chair back onto the mat.

Pros:
Although there is a lot of scuffing and the mat does not look pretty, it has no cracks and is protecting the carpet beneath it.
Delivered in good packaging. The mat was great when I first got it.

I purchased this chair mat to use on a carpeted floor (carpet pile is low about 1/4 inch thick). The mat was in excellent condition when it arrived, and appears to be of very high quality. It is durable and frankly looks pretty nice on my carpet. It is opaque (non-transparent, you can just barely see through it) uncolored plastic, but works well with my generic light-colored carpet. I would say that as far as price point goes (and comparing it with similar products which I did before purchasing) this mat is a very good value, quite cheap for what you get. I use my mat with an office chair, and I do not roll my chair around much as I am usually stationary in front of my keyboard, so the 36"x 48" size has worked well for me (I use a large size office chair with a rolling base diameter of 28" and there is plenty of room for it for the way that I use it).

So on to the downsides: I am a fairly large individual, and my weight (280 pounds) plus the weight of my heavy duty office chair (56 pounds) caused the front of this chair mat to buckle after about a week and a half. The mat did not deform, break, or bend, it just wasn't rigid enough to support that much weight over the top of my soft carpet.

So on to the upsides (and the reason that I am posting this review): I received a couple of e-mails from this chair mat's manufacturer (Iconik Direct) asking me to either review their product or let them know if I had any problems with it. I did contact them about the difficulty with my weight and the front of the mat buckling down. They were very courteous and friendly, and after describing my problem offered to send me a completely different mat which would work better for my personal circumstances free of charge. I really appreciate their customer service and it is a large part of my review here. Although you could say that there was technically nothing "wrong" with the mat that I purchased from them, they have demonstrated an extreme commitment to customer satisfaction (the free replacement that they sent me is valued at about twice what I paid for this one).

So in the end, if you are not a heavy weight gentleman like myself, I would recommend this chair mat, it is of excellent quality, in my opinion quite serviceable, and the customer service of Office Marshall has made my experience with them excellent in getting what I need for a very affordable price. If you are on the heavier side then I will point you towards what they send me as a replacement, which is their Polycarbonate chair mat.

I am editing this review because the company reached out to me and replaced the mat. The replacement was not the same mat, so I don't know if I originally received an older model or what. The original mat was a milky opaque, and the replacement is clear. They are obviously a different kind of plastic.

Their representative wrote that the new mat is a "premium quality mat made from 100% poly carbonate which is much thicker and robust than the PET mat. I can also provide you with the high pile version so that you have added support in the center of the mat which will prevent any curling."

Anyway, the new mat is far superior to the original item that I received, and I have had no problems. So, five stars for customer service, five stars for the replacement mat, and zero stars for the original mat.

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original review: "This chair mat is just awful. I've been using it since Christmas and it continues to move, the spikes underneath are not long or deep enough to keep the mat from crawling, and I have a very short pile carpet. I even have some weights on it at both front corners. I must have had to move it back almost ten times now in just one month. What is more the edges curl up and my desk chair constantly gets stuck on one edge or another. The mat just seems flat when you're not on it, but when you put pressure on it near an edge, the edge curls up.

I just hate it. I so regret purchasing this mat. I will never buy one from Amazon again. My old mat that I got at a big box store almost ten years ago never gave me any problems. This was a poor investment. I'll have to replace it and just accept it as a loss."