LED devices have been commonly produced since the 2 wire pin indicator devices of the 60s. Packaging types continue to progress to suit applications and requirements.
DIP (Dual In-line package) Large 2-pin wire devices where the wire pins go through the circuit board and make electrical contact on the reverse side of the mounting. Typically used in on/off indicator circuits. Multiple devices packaged on board gives a relatively very low lumens per watt.
SMD (surface mounted device) Smaller devices, contact at both ends of package. Mount and electrical connections on the same side of the mounting board permits compact packaging of multiple devices. Gives better 50-80 lumens per watt efficacy.
COB (Chips on board) Even smaller multi SMD style chips manufactured as one integrated very compact package. With a comparatively larger cooling area, better thermal resistance provides higher lighting efficacy.