A 20-meter LED solar string light typically features 200 warm white LEDs, powered by a solar panel and potentially a USB charging option. These lights often have multiple lighting modes and are designed for outdoor use with waterproof features. 
Key Specifications:
Length: 20 meters (65.6 feet).
LEDs: 200 warm white LEDs.
Power Source: Solar panel (with potential USB charging backup).
Lighting Modes: 8 different lighting modes.
Waterproof: Designed for outdoor use.
Charging Time: Typically 6-8 hours in sunlight.
Working Time: Can operate for 15-20 hours on a full charge.
Additional Features: May include a remote control for mode selection and dimming.
Material: Often feature a copper wire for the string.
Spacing: LEDs are typically spaced about 10cm apart.