Master Magnetics 07239 Original Cast Alnico 5 Cow Magnet, 0.50" Diameter, 3" Length, Silver (Pack of 2) The original cast Alnico 5 cow magnet, bright metal finish, rounded ends that has been the favorite of dairymen and veterinarians to prevent Hardware Disease in cattle for nearly 50 years 0.50" diameter, 3" length (12.70 mm diameter, 76.20 mm length), solid, seamless, smooth, cylinder shape with rounded ends, magnetized completely from tip to tip Powerful cast Alnico 5 magnet creates superior magnetic' field projection, consistent pulling force along length, and alignment of tramp iron parallel to magnet It is non-toxic and non-corrosive in use Administer with ordinary balling gun. One magnet works for the life of the cow!