An Analysis of the Distribution of Birthdays in a Calendar Year Bilstein B6 91 95 Spartan MC 2000 29.65in L Rear Monotube Shock Absorber Blue Straight. Bilstein B6 shock absorbers and struts are the ideal choice for improving the performance of any vehicle. These shock absorbers and struts feature a monotube design which provides consistent fade free performance. Bilstein B6 shock absorbers and struts utilize a unique, velocity sensitive, digressive piston which reacts to changing road conditions to provide consistent fade free performance. All B6 shock absorbers and struts are tuned for each specific application to assure optimal performance is achieved. Bilstein B6 shock absorbers and struts offer a significant improvement in ride quality, handling, and comfort.