QA1 27A685M 27 Series Shock Monotube GM Mid & Full Size Rear 5C/5R Linear Sealed IMCAQA1 27A685M 27 Series Shock Monotube GM Mid & Full Size Rear 5C 5R Linear Sealed IMCA The 27 Series is a brand new stock mount monotube shock. Featuring a zinc plated body, 46 MM hard anodized piston and multiple valving options, the 27 Series works like our tried and true 26 Series, but with stock mount option. They are zinc plated for corrosion resistance, and are a popular choice for street stocks, hobby stocks, mini stocks and other classes that