A tun is the largest size of container for beer, and contains 216 gallons. Which is a LOT of beer!
There is a lovely walk, heading both north and south from the carpark at Firkin Point. And the name 'firkin' just kinda begged for a series of caches. There are a range of sizes of container, from fairly large to quite small. The discerning 'cacher will no doubt consider adding GCTP26 to their itenerary alongside this series, seeing as it sits nicely in the middle!