The picture below shows four types of stickgrenades as used on the north-Italian front in the Alps.
Various heads and stickforms.
The left and right grenade could well be made in Germany.

Photo on the right © Jan.
Two Austrian stickgrenades, the top one is the Rohrhandgranate (neu)., the other is the late type M18.
Both have cardboard sticks.
These replacement sticks were used at the end of WW1.

Data for the M18 shown on the right:

Total length: 355mm , stick length: 250mm
Body length w/reinforcement lugs: 140mm.
Diameter stick: 45mm(top) - 40mm(base)