So awhile ago one of my players scavenged metal from a construct monster that used thunder damage attacks and asked to have the metal used to make something. So I came up with an idea for these knuckle dusters, let me know what you think.

Thunder Dusters Rare item (attunement)

While wearing these knuckle dusters your unarmed attacks count as magical. As an action you can cast the cantrip Booming Blade (level 5). With one action you can cast the can trip twice against one target or on two targets within range. A target can only suffer the secondary effect of Booming Blade once by this effect. This item has 2 charges that can cast the following spells for one charge each (DC 14)

Thunderous smite lvl 1 Thunderwave lvl 1

Casting thunderwave in this way the wave the emanates from you in the centre of the cube