Some manufacturers of pulsation dampeners provide items which do not dampen pulsations. Supercapacitors can stabilize voltage fluctuations for powerlines by acting as dampeners. Ford Racing adjustable dampeners and a drag race spring kit. The nose gear was steerable with miniature shimmy dampeners and a lock. Some professionals, such as Andrei Agassi, used rubber bands instead of specialized dampeners. Dampeners are nearly always placed very near the bottom of the racket string bed. Yamaha also included front and rear dampeners to help with stability of the chassis. In September 1941 Flame dampeners were fitted and testing completed. The 5000 series units, introduced from mid-2015, have sound dampeners in-built.