The ultimate in Tether Tugs, the BIG size is the strongest version they have ever made. Nearly 40% thicker than the medium, the BIG is for the biggest, strongest dogs or the 70 lb. dogs that you just know could move a house foundation if it had a tennis ball attached! We are looking at you Pit Bulls, Rottweilers, and German Shepherds! The BIG still allows 360 degree pulling and spinning with the attached rope toy and is held into the ground by a mammoth in-ground base that lets the Tether Tug slide in and out when not in use.