Bracers of Magical Shielding

Most warriors fight with a weapon and shield, but spell-casting warriors tend to break the rules. The Abjuration spell, "Shield" allows a warrior fight as if he had a shield while still keeping a hand free to cast spells or wield a two-handed spell. This is why a majority of warrior mages at least dabble in Abjuration magic simply to pick up the spell though other low circle spells are certainly useful for warriors.

by me with Hero Forge

Sometimes elite warriors keep a potion of Shield or two in their pocket, but potions are not always convenient to use in the middle of a fight, so many adventurers and body guards to the wealthy wear enchanted bracers that hold the Shield spell.
A Wand or Staff of Shielding can be cast on anyone it points to while with Bracers of Shielding can only be cast on the wearer, but Bracers of Shielding can be used hands-free making them popular with elite warriors who want to economize every action.

Manufacturing process

Most Bracers of Magical Shielding are designed to hold 10 or 20 charges which results in 40 drams of reagents or 80 drams of ordinary abjuration reagents respectively to charge them.
The bracers themselves are designed like ordinary bracers and can be crafted by any competent armor smith, but they need to have 10 or 20 drams of durable reagents forged into the metal when initially crafted.
Recharging a spent set of Bracers requires expending the 40 or 80 drams of reagents again. It is the same cost whether the enchanter is recharging 100% of the charges, or 10% of the charges, so most wait till the last minute to reload.
Most Bracers are designed to be used by anyone. If Bracers can only be activated by a mage, the costs goes down 10% across the board.

Item type

Armor

Rarity

uncommon, but more common than most magic items