Tahvo timer
From Guild of Archivists
The tahvo timer measures a period of one tahvo (<dni>tavo</d'ni>) (about 14.5 minutes) in the D'ni timekeeping system each time it is activated. The tick marks on the timer are spaced at intervals of one gorahn (about 34.8 seconds), while the D'ni numerals visible through the magnifying lens indicate the number of prorahntee that have elapsed, in increments of 25. One prorahn is about 1.4 to 1.5 seconds, and there are 25 prorahntee per gorahn, or 625 prorahntee per tahvo.