(later acquired by ) took over the design and production, and released the first 555s in . The full part numbers were NE555 (commercial temperature range, 0 °C to +70 °C) and SE555 (military temperature range, −55 °C to +125 °C). As with most parts of the era, these were available in both high-reliability metal can (T package) and inexpensive epoxy plastic (V package) packages. Thus the full part numbers were NE555V, NE555T, SE555V, and SE555T.
It has been hypothesized that the 555 got its name from the three 5 resistors used within, but Hans Camenzind has stated that the number was arbitrary. The part is still in widespread use, thanks to its ease of use, low price and good stability. As of 2003, it is estimated that units are manufactured every year. The circuit arrangement of the 555 is said to be even more common, being incorporated in the of many single-voltage and other electrically-erasable ICs.