This new BLACK OUTPower Brake Conversion for the 1960-66 Chevy and GMC trucks consists of a 9″ diameter vacuum booster and black POL or Wilwood master cylinder and Black Outadjustable proportioning valve.Performance Online introduced this item in April 2013 and received a huge response. This kits add a nice professional detailed look to your classic. Improves stopping distances and driver performance tremendously.