100year old grenade
At first glance this looks like some unremarkable modern grenade. Closer inspections reveals something over 100 years old.
This is a WW1 French OF1 Grenade made between 1915-1917.
OF1 stands for Grenade Offensive No. 1 The fuze is a Brillant Model 1916 made by ECP - Ecole Centrale de Pyrotechnic - Bourges France.
The body is made of thin pressed tin plate. As an offensive grenade designed for close quarters combat in the trenches, it was all about surprising or stunning the enemy. Fragmentation grenades would most likely injure the attackers as well as the enemy so not a good idea for offensive operations in close confinement.