We are offering energy saving lamps. Operating voltage: 110 - 130v 60hz or 220 - 240v 50hzcolor temperature options: 2700k/6400kwattage: 23 (13w, 15w, 18w, 21w, 26w is available)tube diameter: 12mmoptional base: e27/b22average lifetime: 8, 000hrs/10, 000hrs availableeasily installation high lumen efficiency, high crimodel wattage lumen size h1 size h2 size d tube dia. qty package size(w) (lm) (mm) (mm) (mm) (mm) pcs/ctn (mm) esl034-15 15 825 140 73 54 12 50 640*325*178esl034-18 18 990 148 73 54 12 50 640*325*178esl034-20 20 1100 156 73 54 12 50 640*325*178esl034-24 24 1320 161 73 54 12 50 640*325*188esl034-26 26 1430 165 73 54 12 50 640*325*188 negative ion vitamin in the airion is produced when electron collides with molecule in the air.those with negative charge are called negative ions. They are everywhere in the nature.thundering, photosynthesis of plants and waterfall all can bring a great amount of negative ions.that's why peoplefeel refreshing in thundering weather, the forest or under waterfall. the negative ion can effectively activate the oxygen molecule in the air and prevent air-conditioner related disease. it can improve the function of the lung.when people inhale negative ion, their lung can absorb 20% more oxygen and blow off 15% more co2. it can activate many kinds of enzyme and improve metabolism. It can make people energetic, raise efficiency and improve sleep quality. It can clear the dust and smoke by neutralizing their positive electronic charge and making them fall. It can reduce television and computer's ham to people's eyes and keep tv and computer from dust. Lead time: 30 days fob port: shanghai minimum order: 3, 000pcs sample available.