Hope Vision R4 LED Endurance Front Light: After two years of design and development the new Vision R4 LED lighting system has emerged as the ultimate multi-sport lighting system for a multitude of twilight activities. Endurance version includes 2 x 2 cell battery packs. Combining the latest in LED technology, innovative new ideas in drive circuits, and the highest energy density battery cells available, the R4 weighs in at half the weight of its predecessor – the original Vision 4 – and is 30% smaller, without any loss in performance. In fact the R4 manages to kick out 1000 measured lumens, that's 65% more light output than the Vision 4. Hope have achieved this by designing the lamp around four Cree XPG LEDs, selecting the highest flux bin currently available, and controlling them with one of the smallest and most sophisticated, software based drive circuits ever created. The six power levels are split into two sequences – Race and Trail – each accessible by either a quick press or a press-and-hold of the power button from the off position. The two sequences mean improved usability. The Race sequence contains the three highest power levels, so switching from one level to another is faster and eliminates the need to pass through the lowest level, ideal for those times when maximum light is priority and battery life is not critical. The Trail sequence is there for extended periods of use when only a low level of light is needed but battery life is more of a consideration. The low power level is ideal for close contact use or to reduce glare when map reading. Trail sequence also contains the flash mode (which now pulses from dim to high) for times when ultra high visibility is required from long distance. The light is transmitted through the R4's highly efficient optic to create a diffused uniform light distribution across the entire beam angle with no intense hot-spot in the centre. Both laboratory and extensive field tests were carried out during the development on a range of optics to ensure that beam distance was not sacrificed while distributing the light as evenly as possible throughout the field of vision. The emphasis on the intelligent software within the 'brain' of the circuit allowed fewer hardware components on the PCB, reducing its size. A smaller PCB footprint meant more freedom in design when developing the compact CNC machined housing. The rugged and corrosion resistant anodised aluminium exterior has been extensively machined to create heat fins which maximise the surface area/ volume ratio to dissipate the heat as effectively as possible. Whilst every effort is made to dissipate as much heat as possible from the unit, we also wanted to keep the lamp compact and lightweight so in the higher power levels the housing temperature inevitably increases. Therefore, the circuit includes intelligent thermal management to prevent any permanent damage to the electronics. In most outdoor applications the lamp will operate comfortably, but if the natural airflow is reduced and the unit starts to overheat, the circuit will gradually restrict the supply of power to the LEDs in order to reduce the temperature. This also helps to prolong the battery life by reducing the amount of energy lost through heat. Light Source: 4 x Cree XPG, R5 Bin Light Output: 1000 measured lumens, 1446 generated lumens Beam: Diffused uniform beam (+/- 12.5°) Distance: 105m Mounting: New for 2011/2012 – CNC machined aluminium QR bayonet mount for handlebar, helmet or head Battery: 7.4v Li-Ion, 2600mAh Charge time: 3 Hours Weight: 367g (endurance) Power levels: 6 (two sequences of three), including flash Burn time: 1:15 hrs – 8:00 hrs Endurance version includes 2 x 2 cell battery packs.