Rundlet

The rundlet is an archaic unit-like size of wine casks once used in Britain. It was equivalent to about 68 litres. It used to be defined as 18 wine gallons—one of several gallons then in use—before the adoption of the imperial system in 1824, afterwards it was 15 imperial gallons, which became the universal English base unit of volume in the British realm.

English wine cask units^[1]

gallon	rundlet	barrel	tierce	hogshead	puncheon, tertian	pipe, butt	tun
							1	tun
						1	2	pipes, butts
					1	1+1⁄2	3	puncheons, tertians
				1	1+1⁄3	2	4	hogsheads
			1	1+1⁄2	2	3	6	tierces
		1	1+1⁄3	2	2+2⁄3	4	8	barrels
	1	1+3⁄4	2+1⁄3	3+1⁄2	4+2⁄3	7	14	rundlets
1	18	31+1⁄2	42	63	84	126	252	gallons (wine)
3.785	68.14	119.24	158.99	238.48	317.97	476.96	953.92	litres
1	15	26+1⁄4	35	52+1⁄2	70	105	210	gallons (imperial)
4.546	68.19	119.3	159.1	238.7	318.2	477.3	954.7	litres