Mercury Topaz Window nets are one of the most important elements in safety when it comes to racing. By providing a semi-permeable medium, the window net allows the driver to communicate, breathe fresh air, and escape quickly in an emergency, while being protected from flying debris that one will experience on a racetrack. Furthermore, they will retain the occupant inside the vehicle in the event of a crash. Window nets help improve the level of safety drastically, and when price is considered, they are a precaution that simply cannot be overlooked.

Window nets became mandatory in NASCAR in 1970, after Richard Petty suffered a horrific accident during which Petty's left arm and helmet came out of the window. Luckily he survived, but endured serious injury. Before 1970, window nets in NASCAR were simply optional.