This flare could be attached to a tree or pole and was actuated by a trip wire.
The fuze was almost identical to the fuzes found on US smoke grenades.
On ignition (no delay) , the candle will produce 40.000 candela for about one minute.
These flares were packed 25 in a wooden case, each issued with 3 nails and 13.7meter of trip-wire.

Length: 97mm , Diameter: 64mm.

Scan on the right thanks to R. van Doorn.
Photos below © Patrick.

All photos below Cory

M49A1 :

Dimensions of the M49A1. "grenade"-body only, without the attachments :

height : 120mm
height cylinder only : 105mm
diameter : 39mm
weight : 277gram

Photos below Frank :