LightInTheBox offers the Convoy S2+ 365nm Nichia UV Waterproof LED Flashlight in Black for $14.99 with free shipping. That's $5 under our April mention and the lowest price we've seen. (It's the best deal now by $12.) It features up to a 200-lumen output.

Note: This item ships from China and may take two to three weeks to arrive. Uncheck "Add Shipping Insurance to your order" during checkout to remove the 49-cent fee.