Mm-hmn. Or something like it. [they aren't looking to see the inquiry in Shadow's scowl...until they are and double-take.

blink. frown.] You...don't know what a sending stone is? [okay, more obvious by the look.] Eruh, it's like...it's not always a rock, but it's a small surface that has the Sending spell sealed in it. And, like...uh... [sheesh, they've never had to explain this shit before, it was just there.] It has charges? Per day? To cast.

[they wiggle a finger at their ear with the earpiece.] And beam the spell into your head like these, you know?