If these are being used in Panasonic / Technics equipment to replace the panel illumination bulbs, we recommend that ALL the bulbs are replaced at the same time. This will result in an even light distribution throughout the unit, and if one lamp has blown, the others may also be nearing their life end.
Replacing the lamps involves a certain amount of soldering within the equipment.
To answer numerous emails, the bulbs are NOT coloured blue like in the picture, this is just the way it photographed - the glass is actually clear.