Made by Adventure Lights, the 'Guardian' light is a waterproof and robust unit designed with the outdoors in mind.  It can be easily changed between flashing or constant mode by flipping over the battery when the lens is unscrewed.  Features of the light are:

• Visible up to 1.6km (one mile) away; 
• Waterproof to a depth of 100m (300 fee); 
• Available in white, red, green, blue & yellow; 
• Use CR2032 batteries (same as NK SpeedCoaches); 
• Batteries last up to 250 hours in flashing mode (about 100 hours in steady mode); 
• Lightweight (white bow light is only 75g); 
• No tools are needed to change batteries;
• Can be used with a detachable clip to hats, jackets or straps

Price: $29.00