In 1 atomic unit of mass there is 0 firkin.

assay ton [AT] [long] assay ton [AT] [short] atomic unit of mass bag [Portland cement, Canada] bag [Portland cement, US] bag coffe barge carat [kt] carat [metric] cental chalder clove crith dram [dr] [apothecary] dram [dr] [apothecary] firkin flask gamma geepound grain [gr] gram [g] gros hundredweight [long] hundredweight [short] hyl [cgs] international unit [ui] jin [China] kilogram [kg] kip [kip] last [General] last [US] liang [China] mark metric ton mic millier milligram [mg] mite mite [metric] myriagram [myrg] ounce [oz av] [avoirdupois] ounce [oz] [apothecary] ounce [oz] [troy] pennyweight [pwt] point pound [lb av] [avoirdupois] pound [lb t] [troy] pound [lb] [metric] quarter [imperial] quarter [informal] quartern quintal [q] quintal [q] [metric] rebah sack [Canada] sack [US] sack of flour scruple [s ap] [apothecary] sheet shekel slinch slug stone [st] ton [t] tonne [long] tonne [metric] tonne [short] troy truss wey

assay ton [AT] [long] assay ton [AT] [short] atomic unit of mass bag [Portland cement, Canada] bag [Portland cement, US] bag coffe barge carat [kt] carat [metric] cental chalder clove crith dram [dr] [apothecary] dram [dr] [apothecary] firkin flask gamma geepound grain [gr] gram [g] gros hundredweight [long] hundredweight [short] hyl [cgs] international unit [ui] jin [China] kilogram [kg] kip [kip] last [General] last [US] liang [China] mark metric ton mic millier milligram [mg] mite mite [metric] myriagram [myrg] ounce [oz av] [avoirdupois] ounce [oz] [apothecary] ounce [oz] [troy] pennyweight [pwt] point pound [lb av] [avoirdupois] pound [lb t] [troy] pound [lb] [metric] quarter [imperial] quarter [informal] quartern quintal [q] quintal [q] [metric] rebah sack [Canada] sack [US] sack of flour scruple [s ap] [apothecary] sheet shekel slinch slug stone [st] ton [t] tonne [long] tonne [metric] tonne [short] troy truss wey