Tsarin furlong – firkin –makonni biyu ( FFF ) tsarin barkwanci ne na raka'a dangane da ma'aunin da ba a saba da shi ba. Tsayin tsayin tsarin shine furlong, naúrar taro shine yawan firkin ruwa, kuma lokacin lokaci shine makwanni biyu . Kamar tsarin SI ko mita - kilogram - na biyu, akwai sassan da aka samo don gudu ƙarar, taro da nauyi, da sauransu. Wani lokaci ana kiranta tsarin FFFF inda na 'F' na huɗu shine digiri Fahrenheit don zafin jiki. Duk da yake ba a amfani da tsarin FFF a aikace amma an yi amfani da shi azaman misali a cikin tattaunawar cancantar dangi na tsarin raka'a daban -daban. Wasu rukunin FFF, musamman microfortnight, an yi amfani da su cikin raha a kimiyyar kwamfuta. Bayan samun ma'anar "kowane rukunin da ba a sani ba", da aka samu a cikin makwanni biyu shima ya yi hidima akai -akai a cikin misalai na juzu'in juzu'i da bincike mai girma . Daya microfortnight ne daidai 1,2096 seconds.