This is a good product that can help your swing tempo and sequence. I don't believe it is game-changing, but you will be happy to have one. The price feels a bit much for what it is, so it might be worth looking around for a used one. I'd give this 3.5/5.0 stars.
swing path
Not Obsessed: EyeLine Golf Speed Trap 1.0
I bought the EyeLine Golf Speed Trap to help promote a more in-to-out path. Despite a clever design, it was a purchase I regret and do not recommend you spend your money on it.