Beef femur or tibia bone: 4” Center Bones are a top ten best sellers. Most of these bones will have succulent marrow in the middle of the bone along with tasty meaty pieces left on the bone. Every center bone is dipped in liquid smoke and then slowly roasted. These USA natural beef femur and tibia bones have no artificial ingredients and are best suited for small to medium size dogs. 100% grown and made in the USA.