Source: Eberron - Rising from the Last War

Wondrous item, common (requires attunement by a warforged)

A wand sheath clamps onto your arm and imparts the following benefits:

• The wand sheath can't be removed from you while you're attuned to it.
• You can insert a wand into the sheath as an action. The sheath can hold only one wand at a time.
• You can retract or extend a wand from the sheath as a bonus action. While the wand is extended, you can use it as if you were holding it, but your hand remains free.

If a sheathed wand requires attunement, you must attune to the wand before you can use it. However, the wand sheath and the attached wand count as a single magic item with regard to the number of magic items you can attune to. If you remove the wand from the sheath, your attunement to the wand ends.