Hot Racing's 90mm internal spring air damper shock set for rock crawlers or other custom projects. Features: CNC machined aluminum shock bodies, black anodized CNC machined aluminum upper shock cap with o-ring seal, silver anodized CNC machined aluminum lower shock cap with shock shaft guide, silver anodized Precision machined 7mm stainless steel shock shaft for durability Double o-ring lower shaft seal Internal springs with three rates included: Gold (soft), Black (medium), Silver (stiff) Specifications: Extended center to center length: 90mm (3.5 inch) Compressed center to center length: 62mm (2.4 inch) Overall length: 98mm (3.9 inch) Body diameter: 13mm (0.5 inch) Shaft diameter: 7mm (0.3 inch)