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: Negligible (equivalent to 16 years)
• Dimensions
  • Diameter: 0.90 inch (23 mm)
  • Length:    3.2 inch (81 mm)
• 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 
• 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.
    

Accessories in the package

• One black silicone holder with headband
• Two o-rings
• Extra GITD and black silicone rings