How to measure for replacing missing German Pyramid Paddles.

First you will need a hub (this is the center piece that holds the paddle blades)

If you have an existing hub, then you just need to find paddles for them, otherwise you will need a hub. The hub has three measurements, the diameter of the small hole that the hub mounts onto the long metal center rod as shown here. Measure the diameter of the metal rod, in this case it is 2mm. Measure the diameter hub rod hole, in this case it is 2mm. If you are missing all of the paddles then also measure the full diameter of the hub, in this case it is 1 1/8". If you have a paddle and are looking to replace it, measure the length, in this case it is 3 7/8". If you have a paddle and are looking to replace it, measure the diameter of the nub (this part will fit into the hub hole), in this case it is 4mm. So if you measured correctly, the paddle nub will fit into the hub hole.  If you are missing all of the paddle blades, then you will need to measure from the center of the pyramid to the center of the candle, in this case it measures about 4 1/4". You want the paddle once sized correctly to stick out over and past the candle by about 1/2" or more. This way when the candle is lit, the heat will rise and hit the paddle pushing on it to turn. To recap:

If you need a hub and paddles, measure the rod, with that measurement find a hub that will fit that rod, if the rod is 2mm, then the hub hole will need to be 2mm. Then measure the hub paddle hole, in the example above it was 4mm, so you will need a paddle that has a 4mm nub.

Measure the diameter of the hub and the distance from the center of the pyramid to the center of a candle, in our example the hub dia was 1 18", the center distance was 5", so take half of the diameter of the hub (1 1/8), so that will be about 1/2", substract it from the center distance of 4 1/4" and you get 3 3/4", that is the approximate length of the paddle you will need.

Paddle size conclusion, the nub is 4mm and the approximate length is 3 3/4", if in doubt it is better to get a slightly larger paddle rather than a smaller one.