Led Lenser Keylight K1

Handy mini key-light with energy efficient LED Light Chip
Smart, yet robust aluminium casing; key-ring attachment
Glow-in-the-dark Light Ring makes it easy to locate in the dark
Battery: 4 x Button Cell (LR 41) 1.5V; (included) Battery Capacity: 0.24 Wh; Water Resistance: IPX4; Dust resistance: IPXX; Not Rechargeable
Rotary Switch - turning the head of the flashlight
Luminosity: MAX 13 lumens - MIN 13 lumens; Lighting Range: MAX 16 meters - MIN 16 meters; Battery Duration: MAX 0.25 hour - MIN 0.25 hour

Specific References