Illusionist’s Bracers (GGR p178) Says:
whenever you cast a cantrip, you can use a bonus action on the same turn to cast that cantrip a second time.
However some spells like Create bonfire require concentration.
Under spell duration, the players handbook says:
You lose Concentration on a spell if you cast another spell that requires Concentration. You can’t concentrate on two Spells at once.
Do the bracers allow you to concentrate on two cantrips at once?