These grenades were made in the factory PLASTIKA in Croatia between 1991-1993.
The body has an internal steel balls liner and it is fitted with practice fuze for
M75 grenade, but with an improvised detonator.
Several colour schemes are known.

Total length : 108-110mm
Diameter : 57-60mm
Weight : 360-380gram
Filling : 45gram , various fillers.
Fuze delay : 4 - 5 seconds

BIM grenades :

Another version Goran :


Photos below © Craig.

Here's one with another fuze, is this called `BIM` too?