the tray is for 14' to 17' laptops. Ive a 17' laptop that is nearly 2 years old and was getting too hot to handle. got this tray and noticed an immediate effect (about 20 mins onwards). fan no longer is noisy and its lowered the temps underneath.
whats good about this cooler is that the fans can be adjusted so you can place them where its hottest as opposed to being in a fixed place. ive left them at the default place which is in the centre and doing a good job. Uses 1 usb port to power the fans and the usb connector has a usb port to connect to so you dont lose a usb connection. At time of writing this review ive found that the mousepad area has significantly lowered in temperature and is now much cooler to touch.
All in all a good purchase.