The largets round back cylinder. Large in size, but a nice feature of this fixture is that it accepts various lamps and wattages.

PAR38 Round Back

Finish: Black or White
Lamp: PAR38 or BR40 (90 or 120-watt)
(sold seperately)
Accessories Available: LCTA74 Barndoor & LCTA80 Accessories Holder, LCTA92 Color Filters
UL/C-UL Listed