tt4dTT4D menyajikan berbagai perlengkapan otomotif seperti oli, aki, helm, dan aksesoris motor serta mobil yang mendukung performa kendaraan tetap primaTT4D is based at Stanford University and is run by Jeffrey Decker, PhD, program director, Precourt Institute for Energy, Fu-Kuo Chang, p rofessor of Aeronautics and Astronautics,