Fenix SD20 Dive Torch
Fenix SD20 Dive torch, takes two Lithium 18650 batteries, or two Lithium CR123 batteries (if you are rich or no recharge facilities are available!). Depth rated to 100 metres, and with a maximum output of 1000 lumens.
It has two LEDs, one red and one two white settings. The brightness / duration levels are: 105 lumens for 8 hours on the red setting; 400 lumens for 7.5 hours on the less bright white LED; and 1000 lumens for 3 hours on the top setting of the white LED. The red LED also functions as a battery level indicator.
The SD20 is made of alloy, is durable, and has a double O ring seal. It is operated by a twist-bezel in the headset which is pretty easy to use in-water and with gloves on. It has a regulated output and polarity protection. This is a more spot-beam torch than the SD11, and (in this diver's opinion) is reasonable for cutting through murky sumps, especially when mounted further away from the eyes to reduce back-scatter.
Weight is 245g without the battery, the torch is c. 21cm long and c. 4cm at its widest; compared to the days of up to six C cells per torch (for less light and less duration) its pretty easy to wear a pair on the helmet! It uses a Cree XM - L2 U2 (white) and XQ - E (red) LEDs for those to whom this detail means something!