Technical characteristics of the lamp: with brightness at 15,000 lumens according to the official technical specifications of Osram and not 13,400 as listed in Skroutz's specs, this means that this lamp delivers 100 lumens/watt, which means the energy class it receives is F, a typical performance even though this lighting technology has existed since 1965, but with a 17-20% usual reduction in brightness at the end of its life. The light hue, depending on the chemistry/amount of mercury and sodium, gives the corresponding tone of golden-white/yellowish light or more orange-white light. This particular one has a slightly more orange-white light; of course, from lamp to lamp this may vary slightly, and also when they approach the end of their life, they start to become slightly warmer, acquiring a slightly more orange and sometimes a very, very slightly pinkish hue, though not always. If it turns on and off by itself, it needs immediate replacement so as not to strain the ballast and the starter unnecessarily, as at this point the lamp starts to draw higher voltage to stay lit, but the ballast cannot support what the lamp demands, resulting in it turning off and the starter constantly trying to light it, which strains both the starter and the ballast. This sign indicates that it has already reached the end of its life. The specific one I have in my hands was manufactured in November 2010 in Slovakia—very good, as are the German ones!
Generally, high-pressure sodium lamps have a light hue usually of 1900-2000 KELVIN, there are quite a few at 2100 and some at 2200K, which tend towards a slightly more golden-yellow, and generally from lamp to lamp the hue of high-pressure sodium lamps varies slightly, as does this one which is between 1900-1950K.
Average lifespan: 28,000 hours of daily use, 10-12 hours on average. These are usually capable of lasting at least 8-10 years and in some cases, though rarely, can reach 15 years or a bit more, depending on the lamp's quality. Of course, this is true, but the light output will be noticeably reduced by at least 20-25% and may reach 30-35% in some cases, and they will exhibit a phenomenon (cycling) where they turn on and off continuously until they die completely. For 1-3 years, they usually behave like this, but not always.
Color rendering index CRI: 25—very low! These particular lamps are not made for all applications; the light they emit will distort the colors of objects, so they are mainly for outdoor areas where good color perception is not necessary and are intended for street lighting, highways, bridges, ports, security lighting, exterior industrial lighting, and shops....

Lamp evaluation: It is literally a little diamond of lighting, much better than most LEDs out there, stability, reliability, longevity, beauty, very useful in certain low-visibility situations, fog.... thanks to the yellow/golden-white light it has strong penetration in fog, cutting through it, and thus the yellow light is significantly more visible compared to white light in conditions of limited visibility and fog, usually in mountainous and northern areas and countries. However, these lamps cannot be used mainly indoors where color perception is important; the yellow light will distort the colors of objects!
In terms of longevity and reliability, it is excellent; it is an Osram, quality, Slovenian-made, excellent price at 10.7-11 euros from the Dill Shop store, helpful store, excellent prices!