Polycarbonate chairmats are more expensive, but they're worth it. Vinyl chairmats dry, crack, split, develop holes within a year, esp. on plush carpets. Be careful, though, to match your carpet to a chairmat's specs: if carpet is plush/medium/low-pile, buy accordingly. In any case, buy polycarbonate. Vinyl is a throwaway, so often you'd have to buy several at a time. greatofferstock.com delivers fast and accurately (I previously ordered this exact same chairmat from another online company, and had to send it back, wrong model).