OVERVIEW: The M‑08 is a Russian spherical moored contact mine designed to detonate upon physical impact with surface or subsurface vessels. It is anchored to a specified depth to create maritime denial zones without remote activation systems.

DETAILS: The M‑08 (Model 1908) consists of a steel hull approximately 0.9 m in diameter fitted with chemical contact horns that transmit seawater signals to a percussion fuze. Anchored by cable and buoy, it settles at depths between 15–110 m and carries a 115 kg TNT warhead. When a vessel collides with a horn, collapse of the horn allows seawater entry, triggering the fuze and detonation. Updated variants, such as the M‑08/39, served through the 1960s, and licenced copies or analogs have been produced by North Korea and Iran.

FUNCTION: Once deployed, the mine remains moored at its preset depth until a ship or submarine strikes one of its contact horns. The impact initiates the percussion fuze, activating the warhead and creating structural hull damage aimed at disabling or sinking the target.

NOTE:
IOC: 1908
Operators: Russian Federation; former USSR; North Korea and Iran (licensed copies)
Platforms: Dedicated minelayers, naval support ships; aircraft (historic deployment methods)
Conflict used in: Russo-Japanese War (later adaptations), World War I, World War II, Soviet Cold War minefields, regional conflicts involving North Korea and Iran

SOURCE: Military Periscope: https://www.militaryperiscope.com/weapons/naval-minestorpedoes/mines/m-08-contact-mine/overview/ ; cmano-db.com M-08 entry ; Allmines Russian mine database ; NavWeaps: https://www.navweaps.com/Weapons/WAM_Russian_Mines.php ; KCHF.ru technical profile