Both the club and ball meter speed ratings.
But, the club meter speed rating determines the final meter speed you see on your display.
My ball is rated at 3.5 for meter speed.
Meter speed for my putter is rated at 5.0, driver and wedges are 3.5, 3-wood is 3.0, irons are 2.5.
So the meter speed I see is slowest when I use the putter.
It is a bit faster when I use my driver and wedges, but the driver and wedges are the same speed .
The meter is a little faster when I use my 3-wood, and is a bit faster than that when I use my irons