They work... If they fit together. Be careful to get 2 different halves.
In store it wasn't made clear that they came in different sizes. When we came to use them we find that, out of 2 sets, we had 3 of one end and one of the other. Looking at the labels when preparing to return the one "set" off 2 identical hassles we realised that they come in different sizes and we'd end up using the shortest one...which is far too short to make life easier. When we've spent yet another 24.99 we'll probably have a good set of 'cheap' paddles.