Heavy Stack UpgradePRODUCT DESCRIPTION Yukon's team of pioneers do it again! with the innovative HSU 172. This is the industry's first and only attachment that allows the use of Standard or Olympic plates combined with a selectorized stack. By using your existing plates, any Yukon selectorized stack can become the ultimate weight training tool increasing stack capacity to over 500 lbs. Constructed of premium machined iron with Delron bushings and high grade steel, the