Avi's Rings of Portal Makin'

The attuning creature must be in possession of both rings to attune to them.

These two rings are magically linked, one set with a brilliant and shining topaz and the other with an opaque sapphire.

The rings have four charges and regains these charges when the attuned creature completes a long rest.

As an action, the user can expend 1 charge to create two linked portals on flat surfaces they can see within 100 feet of them, (the user must be able to gesture to each desired location within one round or the charge is wasted) these portals are two-dimensional glowing circles with a radius of five feet. Alternatively, the user can expend 2 charges to perform the action as a bonus action.  The portals last for 10 hours, or until the user creates another pair of portals. Any creature or object in between the portals when they close is gently pushed out the opposite side they originally came from. 

Any creature, object, spell, or attack entering the portal exits from the other portal as if the two were adjacent to each other.

The user can expend 1 charge and touch a portal within five feet of them to double its radius. (10 ft, then 20 ft, finally 40ft)

Notes: Teleportation, Utility, Jewelry