The M15 mine is a large circular United States anti-tank blast mine, first deployed during the Korean War. Essentially, it is a larger version of the M6A2 anti-tank mine, which it replaced. Although the M15 has been superseded by the M19 mine (a plastic-cased minimum metal mine of more modern design), the U.S. retains large stocks of M15s because they are still regarded as reliable and effective weapons. When used against main battle tanks the M15 is primarily a "track-breaker" which creates mobility kills, but has a comparatively small likelihood of causing crew fatalities. However, when used against light vehicles such as APCs or unarmored vehicles such as trucks the damage it can inflict is much more severe. Description The mine consists of a large, circular rounded steel case, with a central pressure plate. In the center of the pressure plate is the M4 arming plug, which has an arming lever which can be set to "ARMED" or "SAFE". The pressure plate sits on top of a belleville spring, which in turn rests directly over the M603 fuze. When sufficient downward pressure is applied to the pressure plate (i.e. when a vehicle drives over it) the concertina spring is compressed. This action transfers pressure onto the M603 fuze which fires, triggering detonation. Because this mine has a metallic case, it is very easy to find it using even the most basic mine detector. However, a complicating factor is posed by the two secondary fuze wells. These enable anti-handling devices to be fitted: one on the side of the mine and one underneath. Additionally, a minefield containing M15 mines may also contain a number of minimum metal M19 mines, plus various antipersonnel mines of different types (e.g. the VS-MK2, SB-33, TS-50, PMA-2 or PMA-3), all of which are specifically designed to be difficult to find using metal mine detectors. Fuzes The M15 mine was originally intended to be fitted with the M600 single-impulse fuze, which contained a glass ampoule of liquid explosive. Unfortunately, the M600 fuze was sensitive to temperature variations and therefore unreliable. For example, freezing temperatures made the mine inert as the liquid froze, whereas temperatures above 50 degrees Celsius could cause the fuze to detonate spontaneously. Just as problematic was the fact that M600 fuzes were inherently unstable, making them dangerous to handle, particularly after having been kept in storage for some time. Because of these shortcomings, the