Your Rebounders are the best seed firmers on the market. They are easy to mount, easy to use.
But the part I like best is how they take the seed from the seed tube and line it up, then gently put it to bed in the bottom of the opened V.
This lets the new seeds awaken to breakfast in bed placed there by Y-Not fertilizer tubes, sending the seeds on a quick, even, and early start on new life.
I have tried other brands of firmers, but prefer the Rebounder by far. My checks have showed 3 to 5 bushel advantage, and very good seed alignment in the seed trench.