maXpeedingrods B1 series is ideal for those who want to change the old worn-out strut but improve handling at the same time. It features height adjustable and maintains the OE ride quality to the greatest extent. Notice: No Top Mount Included. Modification Required If You Use OE Top Mount Application: for Vauxhall Astra G MK4 1998-2004 for Vauxhall Zafira A 1999-2006 for Opel Astra G 1998-2004 (Type: T98, T98C, T98V, T98 / NB, T98Kombi) NOT FOR: OPC, GSI and 2.0 Turbo! (Type: T98MONOCAB) Van only) NOT FOR: 2.0T 16V OPC Specification: Front Lowering 30-75mm (depends on vehicle models) Rear Lowering 25-65mm (depends on vehicle models) Damping : Fix Damping Spring rate Front: 8 kg/mm (448 lbs/in) Spring rate Rear: 3 kg/mm (168 lbs/in) Front spring inner diameter: 62 mm Rear spring inner diameter: 49-60.5 mm Spring length Front: 170 mm Spring length Rear: 210 mm Helper spring rate Front: 1 kg/mm (56 lbs/in) Helper spring length Front: 102 mm Spring Preload advised: 7-10 mm Twin-tube Top