These are the correct size (2 mm diameter), voltage and current for ALPINE head units from the 80's.
To install them properly, follow the instructions:
Desolder the burned or brocken lamp
Carrefully pry-off the green bulb cover
Gently remove the old bulb from the plastic base
Clean the holes in the plastic base with a needle if they are clogged with old glue residue
Install the new bulb in the plastic base
Fit the green bulb cover
Solder back in place
 
Correspond to the following ALPINE part numbers:
65T95274F01
65T95274F02
65T80294F05
65T63304F05
 
Used in the 3339, 5255, 5903, 7142, 7179, 7245, 7270, 7273, 7288, 7296, 7390, 7901, 7902, 7903, 7904, 7905, 7907, 7909.