Omega case backs are often among the most distinctive and recognizable in watchmaking. Many Omega models, particularly those in the Seamaster line, feature the iconic hippocampus (seahorse) medallion embossed or engraved on the case back. The style and detail of this hippocampus logo have evolved over the decades, and experienced collectors can sometimes use these variations to help approximate the production era. Speedmaster Professional models traditionally feature a plain case back with engravings noting the watch's heritage as the first watch worn on the moon, though commemorative editions may feature unique case back designs.
Additional markings commonly found on Omega case backs include the reference number, water resistance rating, case material designation, and the Omega logo. Vintage Omega case backs often display the reference number on the inside surface of the case back, requiring removal to view. The case material is typically indicated by markings such as 'STAINLESS STEEL', 'ACIER INOXYDABLE', or hallmarks indicating precious metal content. Modern case backs may also display the PIC number and Master Chronometer certification details.
Some Omega models, particularly those in the De Ville and Constellation lines, feature exhibition case backs with sapphire crystal windows that reveal the decorated movement inside. The movement visible through these windows often displays the Geneva waves (Cotes de Geneve) finishing, the caliber number, and the Omega name. As with all luxury watches, case back markings and medallions can potentially be replaced or counterfeited, so collectors are typically advised to evaluate case back details in conjunction with the movement, dial, and overall build quality when assessing authenticity.