This duo warmer is ideal for beauticians who have to travel or for professionals who require several warmers as it can connect up to 4 warmers. It fits 2 x 100ml wax cartridge. Fast melting and sturdy for 12 hour daily use. Includes an independent on/off switch with indicator light, no-skid base, patented connection design and with side electrical connectors to join multiple units with only one electrical plug.