At half voltage for the Collins 28 volt lamp, the 1873 has 0.20A but the 757 at 0.08amps running at half voltage would give you even more of a longer life. > >Like said before at least twice, 51 or 1893 or 1891 running at half >voltage could last up to a century if not broken by vibration. Keep The Faith, Jim K9TF/WA9YSD