Review on Seattle Sports FireLid LED: Illuminate your Nalgene & CamelBak Wide Mouth Bottles! by Omar Alradwan

Overall this is a really good product. It's durable, waterproof, and offers a decent amount of light when used on a water bottle. It works better on opaque than fully transparent water bottles. Unfortunately, the main disadvantage is that the rubber seal, which is designed to prevent the lid from leaking, does not stay in place and can fall out at the most inopportune moment. This is my second purchase of this item (the seal from the first one got lost somewhere in the woods).