This Czech Flash-bang grenade is made of an aluminium body with a green plastic sleeve covering it.
The one shown on the right (© Cory) also has an attachment to the base, which served as a weight to smash windows.
Dimensions below are light version / heavy version.

Length w/fuze : 125mm/
Length w/o fuze : 102mm/
Diameter : 55mm/
Empty weight : 135gram/
Filling :

The photos below show the one that I have myself.