U-bend bulbs are functionally no different from straight tubes, but they are designed to be used in places with space limitations. An important dimension is the distance between the ends of the tube, known as the leg spacing, which must be matched to the fixtures’ prong sockets. Typical spacing is 6, 3 and 1.6 inches. The overall length of these bulbs can be as much as 24 inches. Offices often use fixtures that take U-shaped fluorescent tubes as well as retail stores due to the range of colors which enhance display lighting. Modern technology has made fluorescent lights more eco- friendly, reducing the hazardous waste. Another improvement is electronic ballast which creates nearly instantaneous starting, reducing the typical delay, and flicker which is associated with fluorescent bulbs.