To be honest, this coming from someone who's had 4 back surgeries and probably still has bulging discs/a nagging back, I can't see this doing much.
There is not enough pull on your legs to lengthen your spine.
What DOES work (I own one) and what is also recommended by my orthopaedic surgeon is an inversion table:
https://images-na.ssl-images-amazon.com/images/I/71WSkG1hLZL._SL1500_.jpg
I highly recommend you buying one of these, watch out for the maximum weight they can carry though so you don't break your neck falling out of it.
Let me know how it worked out should you buy one!