The M34 grenade is used for signalling, screening, and incendiary purposes.
It may be thrown by hand or launched from a rifle, using the M1A1 or M1A2 grenade projection adapter.

The M34 grenade body is of serrated steel and is cylindrical in shape.
The body has a fuze well liner and is filled with WP.

The M34 hand-rifle grenade has a safety pin which must be removed, and a safety lever which is released to cause the grenade to function.
Newer models also contain a safety clip to keep the safety lever in place, should the safety pin be unintentionally removed from the grenade.

The M34 hand-rifle grenade uses the M206A2 fuze.
It is a pyrotechnic delay detonating fuze.
The body contains a primer and a pyrotechnic delay collumn.
Assembled to the body are a striker, spring, safety lever, safety pin with pull ring, and a detonator assembly.
The split end of the safety pin has an angular spread or diamond crimp.

Release of the safety clip (on newer models only) and removal of the safety pin permit release of the safety lever.
When the safety lever is released, it is forced away from the grenade body by a striker acting under the force of a striker spring.
The striker rotates on its axis and strikes the percussion primer. The primer emits a small, intense spit of flame which ignites the delay element.
The delay element burns for 4 to 5 seconds, then sets off the detonator. The detonator explodes, rupturing the body and exposing the WP filler to the air.
The WP will burn for approximately 60 seconds.

Photo below © Craig.

Check Bernt's E-26 , it looks exactly like the M34 but filled with red paint.
Who knows about this one?