A great 9x19mm round pistol, it has a good amount of damage, handling and rate of fire. Though, the durability is very poor, making it jam frequently. The weapon can be fitted with a silencer, but it greatly decreases its damage.
It is found only with Bullet's partner who needs rescuing from the Bandits. If he is rescued, he returns to the campsite near the entrance to Rostok in the Garbage and there is a slight chance he will be killed by incoming Bandit attacks. It is also possible to find one in a secret stash in Rostok.
The Martha's stats are changed greatly during Clear Sky. The Martha now has the best handling for any 9x19mm handgun while retaining an impressive rate of fire. Even without upgrades, it is entirely capable of being fired at a rapid pace without loosing too much accuracy.
The weapon shares the same upgrade as most pistols and is cheap to maintain, but only a limited amount of technicians can upgrade it. The technicians who can upgrade it include Yar, Thunderov, Garin and Aydar.
This weapon also appears in Call of Pripyat, mostly retaining it's stats from Clear Sky.
Unlike other pistols, when zoomed in the recoil pushes the gun back towards the player rather than up; this allows skilled users to deliver multiple accurate shots to specific body parts of opponents in a very short time. However, apart from that and the full-auto capability, it is inferior in every other aspect to the Walker P9m and .45 caliber pistols. Also, Martha has the worst reliability from every pistols available in game (worse even than PB1s), making it quite invaluable firearm.
This is the only 9x19mm handgun capable of fully-automatic fire with the 3rd tier upgrade and it also has the highest rate of fire of any pistol in the game once fully upgraded with all the rate of fire upgrades. Its caliber can also be changed to use more common 9x18mm rounds at the cost of decreased durability.
Oddly, the CS description mentions that it was used by the US military and police units. Essentially this description fits the M9 pistol mostly known as the 92F, a handgun specially designed by Pietro Beretta for the US Military.
In SoC and CoP however, this description was removed and instead mentioned that it was used by special forces units around the world. The M9 was never officially available to military units outside the United states, which would indicate that these are stock 92s or 92 DS models.