These PAR lamps are designed for the the entertainment industry's "Parcans".
The original workhorse of the Rock and Roll industry and other touring live music events the PAR Can is a simple lantern which uses PAR (Parabolic Aluminised Refelctor) lamps to provide a powerful compact light source.
If you're looking for General Purpose PAR lamps you'll find these in the Reflector Lamps, GU10 or MR16 sections.