I made my own which is from part of an undergravel filter. Just the tube that the powerhead connects too and the plastic bit where it attaches to the undergravel section. Put a bit of netting over the end and then just stick an airstone down the tube near the bottom where the eggs are. The bubbles rising just makes the eggs bounce slightly. Probs haven't explained that very well .

A lot of people just put the eggs in a sieve and have an airstone underneath and the bubbles coming through the sieve make them move slightly. Simple but effective.