Bulb Extensions to extend your bulb further into the modifier.
When using a Parabolic or Beauty dish it is important that light from the side of the bulb reach the reflector.
Please note, there is no magical increase in light output, what is achieved is a better spread of light into the modifier and capturing and reflecting some of the light that would be wasted into the speedring/spider of most modifiers.
Metering close the modifier you will only see the line of sight output from the center of the modifier. Meter from a distance at least 2x the diameter of the modifier
Think of the bulb extension as a way to convert wasted light into proper fill for the inside of the modifier and thus more evenly lit.