This climbs a steep thin crack that tapers down to a seam before making some challenging and somewhat run-out moves (crux) up the face above.
The 10-20
This is on the same southeast side of Arid Piles as The Acid Crack and in the same "alcove" as Popeye. Can be approached via the Houser Buttress Area or from the Lost Horse Road, via Jimmy Cliff.