From The TimeSplitters Wiki

The lasergun has appeared in Timesplitters 2. It is a weak weapon when firing normally, but has chargeable shots that increase in power the longer you hold down the fire button. It has a zooming scope and a shield that can be activated with the secondary fire. The shield blocks other types of energy shots. The weapon does not need to reload, functioning on a battery that depletes while the shield is active, the player shoots or charges a shot. It has appeared in the robot factory level in Timesplitters 2's story mode.