print head

R-Series Print Head (2 Channels per head)
Express 30R & UVx40R/SE printers use 3 heads;
UVx40R PLUS/SE model uses 4 heads
UVx90R/SE model uses 6 heads

PRO & UV2400 Print Head (8 Channels)

UVx60 & UVx90 Print Head (8 Channels)

Strata Series Print Head 
Luna printer
Terra printer