CMOS 16 says this: 10.71 Time The following abbreviations, though not limited to the US system of measure, are used mainly in nontechnical contexts: sec. second min. minute h. or hr. hour d. or day day mo. month yr. year In nontechnical writing, the plurals of these abbreviations, unlike those of length, area, weight, and the like, are often formed by adding an s. 5 secs. 12 hrs. or 12 h. 15 yrs. ------------ Per guidance above, would the abbreviated plural form be "mins."? Also, do these look correct based on CMOS guidance above? I don't think the first example below needs hyphens, because abbreviations with periods are used, correct? a 2 hr. 20 min. 42 sec. finish time (Good per CMOS?) lasted 2 hrs. 20 mins. 42 secs. (Good per CMOS?) Thank you.