The Ultimax 100 is a Singapore-made 5.56mm light machine gun, developed by the Chartered Industries of Singapore (ST Kinetics), and is extremely accurate due to its constant-recoil operating system. The Ultimax 100 is a gas-operated fully automatic weapon with a short-stroke gas piston operating system and uses a locked breech design with a rotating bolt. It fires from an open bolt position and has a non-reciprocating cocking handle located on the left side of the receiver that stays in the forward position during firing. 

This unit has a one hundred round drum magazine, and two thirty round magazines. These weapons use a proprietary magazine attachment system, but standard AR-15 magazines can be easily adapted for use.

Click Here for a video from Forgotten Weapons about the Ultimax 100.