When I bought one of my first ones, it came with the purple stretchie. Since then I've extended the collection and 2 more came with pink stretchies.
When boobalah started working out with me, I gave him the pink one and I continued to use the purple one. He could not believe how much upper body strength I'd gotten. I was holding my hands pretty close together and pulling that thing out in a complete arm span. I'd never used the pink one.
The next day, we traded stretchies. I could barely get that pink one stretched. I had to open up my grip! He was having no trouble at all.
So, what colors do you have? Are there any other ones beside the purple and pink?
Oh, I use the pink one only now. It has much more resistance.