The British Army used several signal grenades from their introduction in the 20th century.
The grenades were used to communicate information through pre-arranged combinations of coloured smoke and lights.
Generally smoke was for daytime use and lights at night but some light producing grenades were suitable for daytime use.
[2] Signal grenades were fired holding the rifle at 70 degrees, the butt on the ground and the rifle trigger uppermost.
[3][a] Rodded grenade type where a 15-inch long rod at base of grenade is inserted into the rifle[b] and fired from barrel with a blank cartridge of 43 grains cordite.