The characteristic shape of bent tubes (2U, 3U, 4U) was designed to maximise the light-emitting surface while maintaining compact bulb dimensions. Our modern LED equivalents preserve this proven format while eliminating the drawbacks of old fluorescent lamps - they turn on instantly, do not flicker, and are completely mercury-free. The 15W and 23W E27 models generate a powerful luminous flux, performing excellently in workshop lamps, basements, and large ceiling fixtures.