Ralph Sampson Hakeem Olajuwon Autographed Wilson NBA Basketball - Prova *Silver This is a hand autographed Basketball of Ralph Sampson/Hakeem Olajuwon on an Official NBA Wilson Basketball. Inscribed HOF, Twin Towers. This item has a Prova Authentication, which comes with a numbered sticker hologram. You can view this item on the Prova website and it shows the item was signed. It was signed either at a public autograph appearance or a private signing. This is a stock photo of the item. Although you may not receive this exact item, the item you receive is virtually identical and brand new in great shape.