Nintendo 64 GameBooster 64 (Europe) (v1.1) (Unl), known as GameBooster 64 (Japan) (v1.1) (Unl) in Japan, is an innovative game console accessory that was released by Nintendo in 1999. It is an adapter that was designed to be plugged into the back of the Nintendo 64 console and allow players to boost the speed of their games. This allowed for faster loading times and smoother game play. The GameBooster 64 also allowed for the use of additional memory cards and other accessories, making it a great accessory for gamers who wanted to get the most out of their Nintendo 64 games. The GameBooster 64 was a great addition to the Nintendo 64 library and helped to extend the life of the console.