300-Watt Equivalent Corn Cob LED High Lumen Daylight (5000K) HID Utility LED Light Bulb

Yes, It has a Standard Base BUT for about $2.00, there is a "Standard to Mogul (LARGE)" Adapter. I'm about to Order 10 of these and need the Adapters to Install these into Wall Mount Outside Flood Lights on a Commercial Bldg that currently has Metal Halide Fixtures/Bulbs. (And in my case, I have to Bypass the Ballasts in MH Fixtures.)

Conditionally, yes. The bulb will fit a standard socket and will take less power than the existing 100 watt bulb so there should be nothing to do but change the bulbs. Be aware, however, that the LED bulb is considerably longer that a standard bulb. As such, make sure you have adequate clearance around the bulb and that it will not be subject to being accidentally hit when you're doing work in the garage.

Ddefinitely, yes

The specs I found for this bulb say 120 to 277 Volts. Has anyone tried to use this bulb in a 220 receptacle?

These do have LED's at the bottom that shine down also as well as the one's one the sides if that counts as down lighting.

I just completed a retrofit of about 20 high bay light fixtures in my old warehouse. I replaced the fixtures' original 400 watt metal halide bulbs (and also removed the ballasts and did some rewiring as necessary) with the Feit 300 watt equivalent bulbs. I used the Home Depot mogul adapter for each fixture (the adapters often did not screw in by hand far enough to make contact with the fixtures' original socket bases so I used a short piece of aluminum bar stock gripped in a pair a Vise Grip pliers to engage the rectangular indentations on the top surface of the mogul adapter. This gave me plenty of torque to screw the adapter all the way down into the original socket). I didn't take any before/after light readings but I am very, very pleased with the output of the Feit bulbs and similarly pleased with the major energy savings the retrofit has achieved. . Each bulb has replaced about 450 watts of original light load (factoring in the load of the original ballasts), there is no incessant buzzing now that ballasts are gone, and the Feit bulbs turn on immediately vs. the several minutes of start up time required by the original 400 watt metal halide bulbs. I won't' hesitate to use the Feit bulbs in the future. Good luck with your project.

what i the size of the bulb?

Yes. If you have a high pressure sodium other metal style light. just disconnect the ballast and got a reducing socket.

From the "Cautions" section of the packaging box: "Use only with a portable table lamp that is provided with a shade. Use in portable table lamps in which the distance from the bottom of the base to the top of the lamp-holder does not exceed three (3) times the minimum base diameter. Added weight of the device may cause instability of a free-standing portable luminaire."

Thanks you all I called Feit and they are sending me a new one I will be buying more from them with this customer service