Thanks @ants_stern for testing xtar D36 5800II and D28 3600 dive lights at Silfra, Iceland.
* D36 5800II dive light with flood and spot beam. 2hrs runtime at Turbo 5800lm.
4200lm, 135° flood beam, 3.8hrs runtime; 1600lm, 8° spot beam, 5hrs runtime.
*D28 3600 dive light, max output 3600lm, runtime up to 2.5 hours at Turbo mode.
Max beam throw 550m with focused beam angle 8°.
* D36 5800II dive light with flood and spot beam. 2hrs runtime at Turbo 5800lm.
4200lm, 135° flood beam, 3.8hrs runtime; 1600lm, 8° spot beam, 5hrs runtime.
*D28 3600 dive light, max output 3600lm, runtime up to 2.5 hours at Turbo mode.
Max beam throw 550m with focused beam angle 8°.