Last year I installed a ceiling fan that used odd 2 pin bulbs called GU24. My first bulb just blew out so I decided to try these adapters to use the cheaper CFLs in the fixture. They worked without any problems and allowed me to use the GE Lighting 68511 Energy Smart CFL 13W (60W spare) 870 lumens. Light bulb with medium base, 6 pcs in the fan. I was worried about how much length they might add and whether they would fit under the dome, but they barely fit. I figured others might be interested in knowing the length of this and other things, so I took a picture and took some measurements. : Adapter length (excluding pins): 1+9/16"/4cm. Total extension lamp length (excluding pins): 19/32" (a little less than 5/8)/1.5cm.