Vintage Bosch magnetic hand lamp trouble light

Vintage Bosch Car Lamp # 0310501001 in used condition. The lamp is stamped with “Bosch Germany 0 310 501 001” and the old “K” logo is near the cable input. The plug has also the Bosch logo. The lamp is dirty, not cleaned and without damages. The grey plastic near the bulb is strong dirty. Possible that there was a heat problem but the dirt can possible be removed with cleaner or abrasive paper. I tested it with 6V and it the bulb burns. The lamp can be used with 6V and 12V, just depends of the bulb. The lamp has a magnet to mount e.g. near the engine. Made in Germany.