Tubular, circular or compact single-ended low-pressure mercury vapour fluorescent lamps emitting long-wave UV radiation between 350 and 400 nm. The UV-B/UV-A ratio is less than 0.1 % (UV-B: 280-315 nm). R (Reflector) lamps have an internal reflector of 200 °. The PL-S /10 lamp consists of two single-ended fluorescent tubes melted together; its lamp base contains a specially adapted starter, providing almost instant starting characteristics. PL-S /10 lamps can operate on the same universal ballast as other PL-S lamps.