This leather collar is manufactured of the best specially selected 100% full grain genuine leather. It does not contain toxic elements which can be harmful for your Bullmastiff. Due to the soft leather, the collar will not rub, cut or irritate your pet's skin. Despite the collar is narrow, it is pretty comfortable. All the fittings are steel nickel plated and will not corrode. The traditional buckle helps to adjust the collar, so it will not be too loose. Due to the D-ring, you will be able to attach the lead real fast! This collar is perfect for everyday usage, but if you want it to serve you and your Bullmastiff longer, use special conditioners and water repellents.