During ww1 different models of practice stickgrenades were used.
These were to be used with a normal pull-friction fuze, but in combination with a small spotting charge.
Bodies had emission holes provided in the side and top, and were painted red.
The spent charges and pull-fuzes could be replaced after throwing.

The photos below show two ww1 practice types, large head and small head.

Photos © Nick.

The two grenades above compared to an early WW2 practice grenade.

The photo on the right © Peter. It shows a different type of connection ring which attached the stick to the head.
On Nick's photos above a similar ring is shown.
He suggested that these connections are normally used with practice stickgrenade from this period.