Gadjet Set is a level 49 Dofus 3 set of 2 items. Its bonus grows with every piece you wear, up to the 2-piece bonus; worn in full it adds +110 Vitality, +70 Strength, +20 Power, +3 Crit % and more.
If you wear this belt upside down and press on it hard enough, you may be able to activate its integrated retromagic module. It has never worked, but you can activate it anyway. Then you can then sell it on to someone even more naive than you.