Most solar butterfly lights use built-in solar panels that charge an internal rechargeable cell during daylight. A light sensor typically triggers automatic illumination at dusk or after dark, so the lights turn on without manual switching.
Battery details vary by product: some listings specify a required rechargeable cell (for example, 1 AA NiMH or 1 AAA Ni–Cd), some state a battery is required but not included, and at least one listing explicitly notes a rechargeable cell is included.
Most items advertise simple, tool-free installation or no assembly at all. Many stakes simply push into the ground and require no wiring or tools.
Listings commonly describe weather-resistant plastics, resin construction, stainless steel components, and some items advertise fade-resistant finishes for added durability outdoors.