T5 tube: 6W/8W/14/21W/28W/35W/49W/54W Much higher efficiency of light source increased from 701lm/w to 951lm/w, the utility efficiency increases by 36%. Reflectance of new material increased from 85% to 95%,the utility efficiency increases by 10%. Shortening of the diameter and optimization of hte operation environment of the light source make the utility efficiency 15% increased. A comparison of the utility efficiency between T5 and T8:(1.36*1.10*1.15)=1.72,72% increased. The above comparison indicates places such as offices and meeting rooms where the even illuminance shall reach 500Lx request 3-lamped luminaries of T8 or T12 type. However, if it is of T5 type, 2-lamped luminaries can work better than them in terms of illuminance and power consumption. It proves T5 to be the more potential more economical light sources. Cap: G5 Average life: 8000h-10000h Dia.: 16mm