The grip is made from Strontium aluminate which is a photo luminescent phosphorous material, it absorbs photons (electromagnetic radiation) & UV rays to charge. It does NOT require direct or indirect sunlight to charge. It will charge well in low level indoor light conditions. Your Eyes Should Be Adjusted to the Dark. Glow time is 4-6 hours. Re-charges with sun light. Package includes: Lucid Glow Grip 2oz bottle (Grip size is the same as standard), Lucid 2oz Liquid bottle, Instructions.