Onitsuka Tiger by Asics - X-Caliber GT (Black/Natural) - Men's: As a result of years of research, the X-Caliber GT was introduced in 1982 as an "All Terrain" running shoe. Emcompassing all of the latest technology of its day, the X-Caliber was most likely to be imitated by other shoe manufacturers. Rubber outsole provides great traction and durability. A true performer, it was kept in line and was rated as the #1 men's running shoe in the October 1984 edition of Runner's World .