HASL, Hot Air Solder Level is a common finish type for PCBs. The PCB panel with exposed copper is lowered into a liquid bath of solder then quickly raised out of the bath and moved passed jets of hot air that clear off the excess solder leaving only the solder on the exposed copper areas. HASL is always with Pb (Lead). Of course, you can choose HASL lead free (no Pb) finish.
