Replacement Seat for Herman Miller Classic Aeron Size B Medium (Black Mesh). Color: Graphite Brand: FOAMON MPN: 123 UPC: 860003555965 EAN: 0860003555965. Product Dimensions: 18″D x 20.2″W x 5.8H. Recommended Uses For Product: Chair. Age Range Description: Adult. Surface Recommendation: Hard Floor. Unit Count: 1.0 Count. Frame Material Type: Plastic. Product Care Instructions: Wipe Clean. Maximum Weight Recommendation: 250 Pounds. Back Style: Solid Back. Finish Types: Powder Coated. Cushion Style: Boxed Edge. Item Dimensions D x W x H: 18″D x 20.2″W x 5.8H. Item Weight: 4.6 Pounds. Item Depth: 18 inches. Item Dimensions: 18 x 20.25 x 6 inches. Seat Depth: 18 inches. Chair Backrest Width: 20.25 Inches. Additional Features: Adjustable Headrest. Reclining Position Count: 1. [Compatible with Classic Aeron Size B Only] Designed to fit Herman Miller Classic Aeron Chair Size B Medium. Not compatible with Remastered models. [Full Mesh Seat Replacement] Complete seat assembly with tensioned black mesh to replace worn, sagging, or torn seats. [Exact Dimensions for Proper Fit] Measures 20.25 inches wide x 18 inches deep x 5.8 inches high for accurate alignment with the original frame. [Durable Graphite Mesh] Strong suspension mesh provides firm ergonomic support and maintains airflow during long sitting periods. [Easy Installation] Pre assembled seat includes instructions for straightforward replacement. No additional hardware required. Your receive the wrong item.