High performance, versatile, all aluminum headlamps which can also be used as general purpose angled flashlights without the headband.

H51 Specs: (cool white version)
Beam Type: 80 degree spill beam spread / 11 degree (3.8 feet at 20 feet) hot spot
High:         H1 200 Lm (0.9 hrs)   or    H2  100 Lm (2.4 hrs) / 140 Lm (1.7 hrs) / 4Hz Strobe
Medium:    M1  30 Lm (10.5 hrs)    or    M2      8 Lm (26 hrs)
Low:         L1   2.5 Lm (3 days)   or    L2   0.2 Lm (16 days)
Light output are out the front (OTF) values. Runtime tests are done using Sanyo 2000mAh Eneloop AA batteries.
The 200, 140, 30, 8 and 2.5 Lumen output levels are current regulated. The 100 and 0.2 Lumen output levels are PWM generated.
Operating Voltage Range: 0.7V - 2.5V
LED: Cree XP-G Cool White (color temperature 6100-6500 K)

H51w Specs: (neutral white version)
Beam Type: 80 degree spill beam spread / 11 degree (3.8 feet at 20 feet) hot spot
High:         H1 172 Lm (0.9 hrs)   or    H2  86 Lm (2.4 hrs) / 120 Lm (1.7 hrs) / 4Hz Strobe
Medium:    M1  26 Lm (10.5 hrs)    or    M2      7 Lm (26 hrs)
Low:         L1   2.2 Lm (3 days)   or    L2   0.18 Lm (16 days)
Light output are out the front (OTF) values. Runtime tests are done using Sanyo 2000mAh Eneloop AA batteries.
The 172, 120, 26, 7 and 2.2 Lumen output levels are current regulated. The 86 and 0.18 Lumen output levels are PWM generated.
Operating Voltage Range: 0.7V - 2.5V
LED: Cree XP-G Neutral White (color temperature 4200K)

H51c Specs: (CRI type LED, warm white version)
Beam Type: 80 degree spill beam spread / 11 degree (3.8 feet at 20 feet) hot spot
High:         H1 130 Lm (0.9 hrs)   or    H2  63 Lm (2.4 hrs) / 80 Lm (1.7 hrs) / 4Hz Strobe
Medium:    M1  29 Lm (10.5 hrs)    or    M2     14 Lm (26 hrs)
Low:         L1   2.8 Lm (3 days)   or    L2   0.3 Lm (16 days)
Light output are out the front (OTF) values. Runtime tests are done using Sanyo 2000mAh Eneloop AA batteries.
The 130, 80, 29,14 and 2.8 Lumen output levels are current regulated. The 63 and 0.3 Lumen output levels are PWM generated.
Operating Voltage Range: 0.7V - 2.5V
LED: Philips LUXEON Rebel (Typical CRI: 85, Norminal CCT: 4000K)

H51F Specs: (flood/floody version)
Beam Type: Floody beam from frosted lens, 90 degree beam spread
High:         H1 190 Lm (0.9 hrs)   or    H2  95 Lm (2.4 hrs) / 133 Lm (1.7 hrs) / 4Hz Strobe
Medium:    M1  28 Lm (10.5 hrs)    or    M2      7 Lm (26 hrs)
Low:         L1   2.4 Lm (3 days)   or    L2   0.2 Lm (16 days)
Light output are out the front (OTF) values. Runtime tests are done using Sanyo 2000mAh Eneloop AA batteries.
The 190, 133, 28, 7 and 2.4 Lumen output levels are current regulated. The 95 and 0.2 Lumen output levels are PWM generated.
Operating Voltage Range: 0.7V - 2.5V
LED: Cree XP-G Cool White (color temperature 6100-6500 K)

H51Fw Specs: (flood/floody + neutral white version)
Beam Type: Floody beam from frosted lens, 90 degree beam spread
High:         H1 164 Lm (0.9 hrs)   or    H2  82 Lm (2.4 hrs) / 115 Lm (1.7 hrs) / 4Hz Strobe
Medium:    M1  25 Lm (10.5 hrs)    or    M2  6.5 Lm (26 hrs)
Low:         L1   2.0 Lm (3 days)   or    L2   0.16 Lm (16 days)
Light output are out the front (OTF) values. Runtime tests are done using Sanyo 2000mAh Eneloop AA batteries.
The 164, 115, 25, 6.5 and 2.0 Lumen output levels are current regulated. The 82 and 0.16 Lumen output levels are PWM generated.
Operating Voltage Range: 0.7V - 2.5V
LED: Cree XP-G Neutral White (color temperature 4200 K)

H51Fc Specs: (flood/floody + CRI type LED, warm white version)
Beam Type: Floody beam from frosted lens, with 90 degree beam spread
High:         H1 123 Lm (0.9 hrs)   or    H2  60 Lm (2.4 hrs) / 76 Lm (1.7 hrs) / 4Hz Strobe
Medium:    M1  27 Lm (10.5 hrs)    or    M2  13 Lm (26 hrs)
Low:         L1   2.6 Lm (3 days)   or    L2   0.28 Lm (16 days)
Light output are out the front (OTF) values. Runtime tests are done using Sanyo 2000mAh Eneloop AA batteries.
The 123, 76, 27, 13 and 2.6 Lumen output levels are current regulated. The 60 and 0.28 Lumen output levels are PWM generated.
Operating Voltage Range: 0.7V - 2.5V
LED: Philips LUXEON Rebel (Typical CRI 85, Norminal CCT 4000 K)

H51Fr Specs: (flood/floody, red tint version)
Beam Type: Floody beam from frosted lens, with 90 degree spill beam spread
High:         H1 95 Lm (0.9 hrs)   or    H2  57 Lm (2.4 hrs) / 76 Lm (1.7 hrs) / 4Hz Strobe
Medium:    M1  19 Lm (9 hrs)    or    M2   9.5 Lm (30 hrs)
Low:         L1   1.9 Lm (3 days)   or    L2   0.19 Lm (16 days)
Light output are out the front (OTF) values. Runtime tests are done using Sanyo 2000mAh Eneloop AA batteries.
Operating Voltage Range: 0.7V - 2.5V
LED: Cree XP-E Red (Dominant Wavelength 620-630nm)

H51r Specs: (red tint version)
Beam Type: 80 degree spill beam spread / 9 degree hot spot
High:         H1 100 Lm (0.9 hrs)   or    H2  60 Lm (2.4 hrs) / 80 Lm (1.7 hrs) / 4Hz Strobe
Medium:    M1  20 Lm (9 hrs)    or    M2   10 Lm (30 hrs)
Low:         L1   2 Lm (3 days)   or    L2   0.2 Lm (16 days)
Light output are out the front (OTF) values. Runtime tests are done using Sanyo 2000mAh Eneloop AA batteries.
Operating Voltage Range: 0.7V - 2.5V
LED: Cree XP-E Red (Dominant Wavelength 620-630nm)

Weight:
1.2 oz (35.8 gram)
2.2 oz (61.9 gram) with an Eneloop AA
3.0 oz (84.9 gram) with an Eneloop AA and headband

Dimensions:
Diameter: 0.90 inch (23 mm)
Length:    3.2 inch (81 mm)

Battery: One 1.5V AA (NiMH, lithium or alkaline). 14500 Li-ion batteries are not supported. Batteries are not included in the package.

Battery Shelf Life: Negligible (equivalent to 16 years)

Features:
Electronic soft-touch switch, with a 200,000 cycle operating life
Smart user interface provides fast and easy access to all brightness levels
Precision machined unibody casing from premium grade Alcoa aluminum bar stock
Proprietary heat sinking design bonds the LED board directly to the unibody aluminum casing, providing unblocked thermal paths to over 94% of the surface area.
Durable natural hard anodized finish (Type III Class I)
Ultra clear lens with anti-reflection coatings on both sides
Orange peel textured reflector
Battery power can be locked out by slightly unscrewing the tailcap to prevent unwanted activations or parasitic drain
Waterproof to IPX8 (2 meters, 30 minutes)

Included Items:
Pocket clip
One black silicone holder with headband
One GITD silicone holder
Two o-rings

Operations:
This light has 3 main levels (High, Medium, and Low). Each main level can be configured to one of its two sub-levels. The second sub-level of the High can be further configured to different brightness levels or strobes.

Basic Operation:
Short click turns on the light to High or turns off the light.
Long click (press and hold for about 0.6 seconds) turns on the light to Low.

Advanced Operation and Configuration:
Short click turns on the light to High. Short click again quickly to cycle from High to Medium, and Low.
Press and hold to cycle from Low to High, release to set. When press and hold, the light always cycle from Low to High regardless which level you are currently in.
Double click to toggle and select between the two sub-levels for that main level. Sub-level selections (except the strobe) for the 3 main levels are memorized after the light is turned off and through battery changes.
The second sub-level of the High can be configured after 6 double clicks. Double click (startng with the 7th) to cycle and select different brightness levels or strobes. Short click to turn off the light when finishing configurations. The selections for the second sub-level of the High are memorized after the light is turned off and through battery changes.