Jordan's Explosive Vest

Very Rare This vest which can be hidden under your armor an investigation check against your passive Slight of Hand can find find the vest
The vest when triggered by the command word of the user's choice causes an explosion centered on yourself. The explosion expands in a 30ft Radius. Everyone in the blast must make a DC 15 Dex saving throw. On a failed save they take 15d8 Magical Bludgeoning damage or half as much on a success. The wearer of the vest takes only half damage being protected by the vest.
Once used in this way, you will need to repair the vest before you can use again, making 3 Tailors 3 Alchemy; DC 24 checks