Bilstein B4 R/F Shock for Vauxhall Astra Mk4 Est 1.2 16v (55 kW). Check Out Our Feedback. Bilstein B4 Shock Absorbers – the original mono-tube gas pressurised shock absorbers. The benefits of Bilstein B4 at a glance: – Constant damping power under any load – High power reserves for maximum safety – Drive as though […]