Amphibia

The Amphibia compression sealing system is a functional signature

A genuine Amphibia seals via a caseback + threaded locking ring bearing on one large flat rubber gasket (compression load, not a conventional O-ring), plus a thick domed acrylic crystal that flexes inward under pressure — the seal tightens with depth (~20–30% gasket compression at 200m). The two-part crown wobbles freely: this is a deliberate design feature protecting the stem, NOT a defect or fake indicator.

Interchangeable parts are legitimate — judge the movement and case, not the peripherals

Bezels, dials, hands, crowns and casebacks cross-fit across decades and are widely swapped (Meranom, Murphy bezels, etc.). A non-original bezel/dial/caseback is usually a genuine mod or service part — classify as authentic-but-incorrect / modified, NOT counterfeit, unless the movement or case itself is non-Vostok.

Dial text and origin marking date the piece

Brand text appears as 'Восток' (Cyrillic), 'Vostok' (Latin) or 'Wostok' (legitimate Soviet export spelling). 'Антимагнитная' (antimagnetic) is a period-correct Soviet marker. 'Сделано в СССР / Made in USSR' = Soviet era; 'Made in Russia' generally from ~2001; ~1992–93 transitional dials often carry NO origin line (period-correct, not suspicious). There is no legitimate factory 'КГБ/KGB' dial — those are souvenir/aftermarket. Too-crisp or wrong-font vintage dials are often redials of a genuine watch (originality uncertain), not counterfeits.

Caliber must be a genuine Vostok 24xx with matching jewel count

Genuine calibers carry the caliber number engraving (e.g. 2416B, 2409) and a period origin marking. The 24xx family shares a 24.0mm plate, 19,800 vph, ~31h reserve and Glucydur balance. A '2416B' claiming other than 31 jewels, or a movement of non-Vostok architecture, is a red flag.