I cannot seem to find bulbs for this fixture. It is a 6 in. round recessed fixture intended for a single HID or fluorescent bulb, which was installed by the previous owner.
It contains a fluorescent bulb, but the bulb has no useful markings as to the manufacturer.
Attached is a photo of the label from within the fixture that contains additional details.
--Additional Info, based on comments--
Thanks for the quick response. As I understand it A19, PAR38, and BR40 refer to the size and shape of the bulb--not the type and size of the base. For example, an A19 or an A21 bulb usually have an E26 base (i.e., the part that goes into the socket). The socket of this fixture accepts an E26 base.
I interpreted the label to mean that only HID and Fluorescent bulbs should be used with this fixture, and using a CFL or incandescent bulb would not be OK. The existing fluorescent bulb is a 3 in round globe with an E26 base; it is labelled as a self-ballasted bulb.
Any suggestions for a replacement bulb are appreciated.