Racket stringing is a mechanical process that can best be performed with a mechanical system. Stringway has been using 2 simple and highly reliable mechanical components for their mechanical machines for many years, the weight and the spring.
The M machines have been using the “automatic drop-weight system” since 1984 and the foot-operated MS200 has been using a spring as the “drive system” since 1992.
The light weight MS140 also uses a spring system as “drive” and this system is very simple and easy to calibrate by the user  and ultra reliable.