length difference btwn Speedo and Dolfin square legs

Hello, Just getting back in the pool as my son, who is 5, is joining the local swim club. I want to get a square leg and wondering about the length of Speedo Endurance Square Leg and Dolfin Poly Solid Aussie Square Leg. From the photos at swimoutlet.com, Speedo looks longer, but I am not sure. Speedo: www.swimoutlet.com/.../7888.htm Dolfin: www.swimoutlet.com/.../3363.htm I'd appreciate if someone can post the length of their square legs (either one) to share. Also, do these roll up at all as you train?? Thank you! Hyper