Incandescent phenolic. 4 terminals with tri-drive screws. Fits 3-1/4" & 4" boxes, with cage neck. Quality materials, durability, and time-tested design. 250W 250V White Incandescent phenolic Pull chain lampholder 4 terminals with tri-drive screws Fits 3-1/4" & 4" boxes, with cage neck Ul, box.