The #259 is a direct replacement for the #555 but has 5000 hour lifespan instead of #555's 3000 hours.
Avg. life: 5000 hours
Bulb: T-3 1/4
Base: Miniature Wedge
Average Life is the rated average life that is obtained in closely controlled laboratory conditions of lamps at their design voltage. It is the life point where 50% of the test group are still functioning. Average Life is not the same as service life; shocks, vibration, voltage fluctuations, temperature and other environmental influences may result in a shorter service life.
Approximate Mean Spherical Candlepower (MSCP) is the initial MSCP at the design voltage. This is the generally accepted method of rating the total light output of miniature lamps. To convert this rating to lumens, multiply it by 12.57 (4pi).