Most Edison-style warmers use a candelabra Edison screw base (E12); some models accept the standard medium Edison screw base (E26).
Incandescent bulbs shown with these warmers range roughly from 15 watts up to about 40 watts; an LED replacement example is listed at about 15 watts.
Many of the warmers are ceramic; at least one option in the listings is metal with glass details.
These warmers are electric and are designed to plug into a wall outlet for operation.
The listings reference several shapes, including G50 and T20 incandescent shapes for the E12 base and PAR38 for medium E26 replacement bulbs.
The bulbs and warmers are described as giving a warm glow or warm white light; one LED listing specifies a 3000 Kelvin (3000K) appearance.
These are electric wax warmers designed to melt wax melts or fragrance oils, and some listings explicitly state they include a removable wax melt tray.