Please note that this is the flood version of the H51 and the specs below are for the regular H51. The H51F has a frosted lens, which does a great job of smoothing out the beam and making a very nice flood light, but it greatly reduces throw.
Main Features and Specifications
LED: Cree XP-G Cool White (color temperature 6100-6500 K)
User Selectable Modes: 3 (High, Medium and Low). Each mode can be configured to one of the two sub-levels.
Light Output
High:        H1 200 Lm (0.9 hrs)  or   H2 100 Lm (2.1 hrs)
Medium:   M1  30 Lm (12 hrs)   or   M2     8 Lm (39 hrs)
Low:         L1  2.5 Lm (3 days)  or   L2   0.2 Lm (19 days)
Light output are out the front (OTF) values. Runtime tests are done using Sanyo 2000mAh Eneloop AA batteries.
Voltages: 0.7V - 2.5V
Battery: One 1.5V AA (NiMH, lithium or alkaline). 14500 Li-ion batteries are not supported. Batteries are not included in the package.
Parasitic Drain:Â Negligible (equivalent to 16 years)
Dimensions
Diameter: 0.90 inch (23 mm)
Length:    3.2 inch (81 mm)
Weight
1.2Â oz (35.8 gram)
2.2 oz (61.9 gram) with an Eneloop AA
3.0Â oz (84.9 gram) with an Eneloop AA and headbandÂ
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)
SCHOTT ultra clear lens with anti-reflection coatings on both sides
Orange peel textured reflector
Glow In The Dark (GITD) silicone ring near the tail cap
Battery power can be locked out by slightly unscrewing the tailcap to prevent unwanted activations
Waterproof to IPX8 (1 meter 30 minutes)
Operations
From Off
Short click turns on the light to High instantly. Click again quickly to cycle from High to Medium, and Low.
Press and hold to cycle through Low, Medium and High, release to set.
When On
Short click turns off the light.
Press and hold to cycle from Low to High, release to set. The light always cycle from Low to High regardless which level you are currently in.
Double click at any level to toggle and select between the two sub-levels for that level. Medium and Low selections are memorized after the light is turned off and through battery changes. H1 is not memorized.
