The Mongoose BattleMech was introduced in 2660 as a deep recon 'Mech and a direct competitor and hopeful replacement for the Locust. As the Mech reached SLDF units though it was found that the Beagle Active Probe on the Mongoose gave it extremely good command and control features that endeared it to light 'Mech command lances and led to the Mongoose becoming a front line unit on the battlefields of the Star League and in just eight years the Mongoose was the standard issue command ‘Mech for recon lances.
The Kell/D Chassis used for the Mongoose uses Endo Steel construction techniques, that combined with the use of an all energy weapon armament and standard engine makes the Mongoose a very sturdy and hard to kill machine.
The weapons on the Mongoose consist of three Sorenstein Medium Lasers and one Starflash Plus Small Pulse Laser. This light laser array, while not as deadly as most pilots would prefer, is typical of light 'Mechs and makes the Mongoose a highly independent unit that does not need to rely on a supply chain of ammunition for its survival when on recon duties.
- MON-67 - The MON-67 is the downgraded version of the MON-66 Mongoose. The MON-67 removes the Beagle Active Probe and replaces the Endo Steel Structure with a standard structure. The Small Pulse Laser has been replaced with a standard Small Laser and the Armor has been changed to standard plate armor. To keep the same level of protection as before half a ton more armor has been added to the Mongoose
- MON-76 - The MON-76 is the most high tech variant of the Mongoose to date. The original electronics, weapons, engine, and cooling system have been stripped from the chassis and a complete rebuild of the 'Mech has occurred. As far as the engine the original Nissan 200 was replaced with an XL version and includes a MASC system allowing for incredible bursts of speed. Next the standard heat sinks originally on the 'Mech were replaced with double strength units. The original Beagle Active Probe was replaced with a Guardian ECM suite to allow the Mongoose to interfere in enemy electronics and finally the original Medium Lasers have been replaced with Medium Pulse Lasers and the Small Pulse Laser has been replaced with a standard Small Laser.