Technique: Glyph of Counterspell

Technique: Glyph of Counterspell is a recipe used in Inscription (a technique).

Source
This technique is sold for by the following NPCs:
 * at Honor Hold, Hellfire Peninsula
 * at Thrallmar, Hellfire Peninsula
 * in Scribe's Sacellum, Dalaran

It is limited supply, but has a fast respawn timer (approximately 1-2 minutes).