B12 Series Pro-Kit Front and Rear Lowering Kit (46-000132) by Bilstein. Quantity: Sold as a Kit. You will impress others with the sporty lowering and yourself with the fantastic handling: precise responses, dynamics and comfort rolled into one. Gas Pressure Technology. Over time, the mono-tube gas pressure technology developed by BILSTEIN has established itself as a standard in automotive construction. This technology involves keeping the oil in the absorber under pressure, which prevents it from foaming when temperatures and loads are increasing. As a result, full damping power is retained even when the system is placed under extreme stress, a feature that can be observed in the self-lowering piston. Mono-tube Upside-Down Technology. The original and best: The original mono-tube gas pressure shock absorbers bore the BILSTEIN name, and were still responsible for producing the best there is. BILSTEINs mono-tube technology is the number-one choice in motorsports and series-production