This grenade is identical to the M50P2 and M52P2, but issued with a modernized fuze, the
PU M-69.
The grenade body was marked as a normal M50P2 or M52P2 but the fuze was marked on the top of it's protective cap as M-69.

Factory RZK(REMONTNI ZAVOD KRAGUJEVAC) was replacing old M-50 fuzes on M-50 and M-52 grenades with these new
PU M-69.
These modernized grenades with the new fuze were called M50P2 and M52P2.
M50 grenades were modernized with the
PU M-69 fuze first, the M52 grenades were altered after that.

The project of modernizing M-52 grenades with the new fuze started in RZK factory in 1969, so they called that modernized grenade M-69. M50P2 and M52P2 represent the same grenade.

Total length : 105mm
Diameter : 50mm
Weight : 500-550gram
Filling : 88-105gram TNT
Fuze delay : 4 - 5 seconds

Scan above on the right thanks to Ivica.
Photo on the right H. v/d Zwet.
Information and photos below © to Goran.

M50P2 (same as M69) :