F means that the product is rated in its category in terms of energy efficiency. The Energy Labeling system is based on EU Regulation 2017/1369/EU. F Philips LEDtube EM T8, 16 W, 36 W, G13, 1600 lm, 15000 h, Cool white Philips LEDtube EM T8. Bulb power: 16 W, Equivalent bulb power: 36 W, Fitting/cap type: G13, Luminous flux: 1600 lm, Bulb lifetime: 15000 h, Light colour: Cool white, Colour temperature: 4000 K, Beam angle (max): 240°, Color Rendering Index (CRI): 80, Power factor: 0.5