Review on Dr.Foot Height Increase Insole For Leg Length Discrepancies, Heel Spurs, Heel Pain, Sports Injuries, And Achilles Tendonitis - Adjustable Orthopedic Heel Lift Inserts With 3 Layers For Comfort (Beige) by Ashley Gauthier

I bought it to compensate for my right leg being shorter than the left. The difference is just a few millimeters. But over the years, with exercise, lots of walking, and especially after a sprained knee, the asymmetry led to deep knee pain. I wish I had found this product sooner. I've been wearing it for 3-4 weeks. It has helped the pain to go away and I think it's allowing my weak knee to strengthen since the correction forces the longer leg to work less. I suggest to place it BETWEEN the shoe and the standard foot insert that comes with the shoe (rather than on top of the insert). This way the product won't slide. If you have knee problems due to unequal leg lengths, give this a try