These disc magnets are 0.250 inch (6.4mm) diameter and 0.100 inch (2.5mm) thick. They are magnetized through the thickness. They are composed of grade 40 neodymium iron boron magnetic material and are plated in nickel-copper-nickel for a shiny corrosion resistant finish. Their individual pull force is approximately 2 lbs. Maximum working temperature is 176 F (80 C).