I have 3 types of practise balls and these are the only ones i can use my long irons/woods & driver with. These balls are fantastic for working on your swing - i have a tendency to slice my drives and using these balls to ensure my club path is moving from in to out to avoid the slice!
I've spent hours hitting these - the only downside is if you do catch one slightly wrong they will fly off to the left or right!
Highly Recommend!