HP 393565-001 - Base enclosure (chassis bottom) - For De-Featured (DF) models - Does not include the speaker assembly Retail
HP 378231-001 - CPU base enclosure (chassis bottom) - Includes speaker assembly - For use with full-featured (FF) models Retail
HP 383922-001 - CPU base enclosure (chassis bottom) - For de-featured products - Does not include the speaker assembly Retail