The type of jump rope you choose can certainly help with double-unders. If you’re curious of the best rope available, I would recommend any of these.
But buying a $50+ rope won’t help you get your first double-under. Instead, it will turn 20 double-unders in a workout to something more like 80.
In basketball, that would be like buying a new ball in order to become a better shooter. Although the ball might help with minor details, you should be able to make free-throws with any ball.
Here are three drills to help you get better at double-under technique:
Efficiency Tips For Double-Unders.
But when you do decide to buy your own rope, here’s a short video I put together on how to properly size and fit it.
10 Rounds For Time: