These handy flashlights are inexpensive yet very efficient and bright.
NEVER Needs Batteries!
They are completely rechargeable by simply squeezing the handle which generates and stores power.
A good use for these is to "place and forget" them in key locations (glove compartment, basement stairwell, go kit). Since they don't need batteries, you will have emergency light even if you forgot to swap out batteries in other places (which you should do every 2 years, btw)