The Google provides the Soldier a way to see very far with its 5X Zoom.
Nightvision Googles :
For Nightmissions these UV light enhancing NVGs gives the Soldier the ability to see at a minimum of light. However you wont be able to use a Scope while wearing them and the aiming gets more inaccurate.
The Radio gives the Soldier the ability to talk to his Teammates with the inbuild Voice over Net communication or a radio command. Nearby enemys will also hear what is said. If it is damaged you loose the ability to talk to teammates over long distances and to receive commands by the PlatoonLeader. Your only ability to communicate is to shout then.
The Flarelauncher is used to enlight the environment and for giving signals to a Medic or an Engineer.
The Kevlarvest is made of strong Kevlar, giving it the ability to slow down most bullets, lowering the damage or even stop Bullets with a low Muzzle Velocity (like a Bullet fired from a 9mm Handgun).
The Kevlarhelmet is also made of Kevlar. It provides protection against shrapnels and bullets hitting the helmet in a low angle. However you can still die even if the bullet is stoped as your neck can brake because of the high muzzle velocity of the bullet.