Thin wood and thinner metal weave together to form a tapered cylinder designed to be worn around the forearm like a thick bracer that wraps all the way around the arm. It hinges open and locks securely around a creature's arm, changing size to fit the wearer as needed. Once locked in place, a metal bracelet encircles the wearer's wrist, with four markings equidistant around the circumference. The wearer can rotate the bracelet, and the markings click into place when lined up with an indentation cut into the top.
A sliding plate in the top of the bracer exposes a thin extradimensional space, just the right size for a wand or maybe a stack of coins in a pinch. Each time the bracelet clicks into a new slot, another extradimensional space opens for use. The Sorcerer's Secret can hold 4 wands in all, one in each slot. Switching the wand slot in combat takes a bonus action. The wearer may conceal the Sorcerer's Secret easily within the sleeve of a robe.
When a creature wears and attunes to the Sorcerer's Secret, the wearer gains the ability to attune to a wand stored in one of the extradimensional slots without counting toward the normal attunement limit of three items. As the wearer advances in experience with a spellcasting class, they attune to more wands in the Sorcerer's Secret's extradimensional spaces for free, attuning to two at 7th level, three at 13th level, and all four at 19th level. They can use the wand in the currently-selected slot as if holding it in their hand, leaving their actual hand free.
If the Sorcerer's Secret loses attunement for whatever reason, any contents stored in its extradimensional spaces will instantly appear next to it and clatter to the ground. A creature may not wear more than one Sorcerer's Secret simultaneously or they both immediately lose attunement, ejecting anything stored in extradimensional spaces as above.
Lydianna created this device and made it the signature item for her business The Sorcerer's Secret. She improves the design all the time. Lydianna recently mastered using tiny extradimensional spaces, so this latest iteration is the smallest and lightest version yet. Eventually she hopes to shrink it to the size of a normal bracer, enhancing its stealth.