The Pipe Bomb is a timed explosive with a big blast. It deals more damage than a frag grenade, so use it on tight groups of soldiers or on light vehicles.
Throw it into a cluster of enemies or next to a vehicle. Since it runs on a timer, give yourself room before it goes off.
A frag grenade is more common and focused on foot soldiers. Dynamite is aimed at vehicles. The pipe bomb sits in between with raw damage.
Bait
Bait is a chunk of meat you throw to draw predators to a spot. Toss it near FND soldiers and let the local wildlife do the fighting, or use it to bring out animals while hunting.
C4
C4 is a remote-detonated explosive you place and trigger when the moment is right. It is your best tool for setting traps on roads, wiping out parked vehicles or blowing up a target without being nearby.
Dynamite
Dynamite is a timed explosive built for wrecking vehicles rather than soldiers on foot. Throw it under an armored car or tank and get clear before the fuse runs out.
EMP Grenade
The EMP Grenade shuts down vehicles, cameras and alarms in its blast. Throw one before you sneak into a base to blind its security, or stop a vehicle dead in its tracks.