Here's what other sites are saying:
Just replace the cap on any standard (2" wide mouth) water bottle with this light-weight, ingenious cap and you'll have light all night long. The polycarbonate LightCap200 has four super-bright white LEDs for lots of light and the tiny built-in solar panel charges the replaceable AAA NiMH battery to full capacity with just eight hours of sunshine.
- Vargo Outdoors
Turn your wide mouth water bottle into a super-bright solar powered lantern with the SOL LightCap 200.100% solar powered, no batteries to replace, and you get up to 8 hours of bright light when fully charged. Fits all standard 2.25" diameter wide-mouth bottles, including Camelback , Nalgene and GSI . Four Super Bright LED lights with a light sensor that automatically turns power off during the daylight to conserve power. Go Green - Go Solar! Bottle sold separately.
- Altrec Outdoors
SolLight Lightcap 300
Black Diamond Apollo
$37 - $49
Ultimate Survival Technologies Pico Lantern
$20 - $29
Mammut Ambient Light Dry Bag Battery-Powered Lantern / Dry Bag
Goal Zero Lighthouse 250 Lantern
Princeton Tec Helix Backcountry
$30 - $35
BioLite PowerLight Mini