Most indoor / outdoor carpet is made from olefin. Olefin is a synthetic fiber that is constructed from polypropylene or polyethylene. Olefin's benefits are its strength, colorfastness and comfort. Furthermore, it is resistant to stains, mold, mildew, abrasion and sunlight. Because it is hydrophobic, olefin is often utilized outdoors and for marine carpet. This fiber dries quickly when wet, which is why it is not prone to mold or mildew. Additionally, being solution-dyed makes the fiber extremely fade-resistant. So, exposure to sunlight and UV rays will not discolor the carpet. It can often be used interchangeably with some commercial carpets that are made to the same specifications.