The four ounces of "Sand of Time soaked by the Night" that Shard found from his own timeline were intended for purchasing a gear in this clock shop, as part of assembling the Compass pointing to the End Point.
When the two of them returned to the counter and opened the inventory list, the price of that gear hadn't risen. After Shard expressed his wish to purchase it, sounds of gears turning, axles grinding and pistons pushing came from within the wooden counter, followed by a click, and a drawer popped out on the exterior of the counter.
Shard placed the prepared Sand of Time into the drawer and then pushed it back into place. After waiting for a moment, another drawer popped open, containing the exact gear they were looking for. The inside of the gear was just the right size to fit the base of Fiona's Compass, allowing the compass base to be locked inside the gear.
