Ball Bearings of the Eagle

These ball bearings come in a finely gilded set of 25. As an action, you speak the command word and the ball bearing marks all creatures within a 60ft. radius for the next minute. For the duration (1 hour), creatures marked in this way are revealed to you with a faint red aura.If you cannot see the aura, you "feel" it like the spell locate creature. If a marked creature teleports on the same plane of existence as you, you know where. If a marked creature teleports to a different plane of existence, you know wich. 

Notes: Enchantment Cost 5,000 GP (200 GP Each)