Fluorescent lamps of 20W or 40W for starter less ignition, to be operated by means of special explosion-proof ballasts on A.C. mains; the lamps are designed specifically for application in areas where an explosion hazard exists. "TL"X instant-start lamps, stabilized by special ballasts, are provided with an internal ignition strip connected to one of the electrodes. Since the electrodes are not pre-heated, only one electrical contact is required at each lamp-end. To exclude all possible sparking effects during ignition, the caps and, in particular, the long, thick lamp-pins are constructed so as to ensure maximum contact with the appropriate lamp holders. Application: In "flameproof" and "increased safety" luminaries designed in accordance with IEC 79/1, 79/7, EN 50018 and 50019, VDE 170/171 and similar specifications, both for indoor and outdoor applications.