Simple, like all genius ideas, the grenade slingshot is exactly what it says on the tin. An ergonomically designed, advanced elastics, composite slingshot with a cup seized specially for standard issue hand grenades.
It significantly increases the range at which grenades can be employed, but as it merely assists in propelling the projectile via muscle power, it is not subject to the legal restrictions placed on grenade launchers.
A grenade slingshot weighs 0.3 kg.
Retail price for the little weapon is 5c.
A grenade slingshot doubles the throwing range of hand grenades.