Original Citizen case gasket with reference 393-2027 , from unused old stock (NOS). The part comes from the original Citizen spare parts series (“純正部品”) and was used as packing (cushion) for various Citizen vintage cases.
The official Citizen service document lists 393-2027 as the seal for the model:
Citizen 51401
(as well as identical or compatible cases with identical case construction)
The gasket serves to seal between the case body and the back cover, restoring the original dust and moisture resistance of the watch case.
Technical details: • Part number: 393-2027 • Function: Housing seal / Packing (Cushion) • Category: O-ring / seal • Compatible: Citizen 51401 (and similar models) • Condition: NOS, unused • Packaging unit: Original Citizen 5-piece bag
Origin: Original Citizen Japan spare part – “純正部品”
