Tein EDFC:

The Tein EDFC works with the Flex and Mono Flex coilovers to allow for in-cabin adjustment of the shock absorber stiffness. By installing electric motors on the strut tops, ride quality can literally be adjusted at the push of a button. In addition, you can set 3 presets for different types of driving (i.e. city, hi-way, and track); adding to the versatility of your Tein Flex or Mono Flex coilovers. The EDFC can control the 16 different stiffness settings and can also be put into 32 setting mode which adjusts in half-step increments for the purists and control freaks. The compact (approximately 3.5″ wide x 1″ tall x 4″ deep) control box is easy to mount, making it a great add-on.