Set of 14 magnets Size completed ring: 43mm OD x 39mm ID x 5mm Long Material: Neodymium (NeFeB). Grade: N45H Coating: Nickel (Ni) SKU# MMOT433905 OD = Outer Diameter ID = Inner Diameter N45 equals very strong magnetic material. The "H" represents a high heat rating. Standard neodymium magnets - those with no extra letter after the number rating - will produce their maximum strength up to 176 degrees F. Beyond 176, standard NdFeB magnets begin to lose strength. These N45H magnets will maintain full strength up to 248 degrees F - perfect for applications which require high heat tolerance - such as some motors. ASSEMBLY REQUIRED: These magnets will be sent as 12 arc segments - 6 with N Poles on the outer diameter and 6 with N Poles on the inner diameter. PLEASE NOTE: As with ALL neodymium magnets, these arc segments are very fragile. Therefore, 2 extra arc segments will be included with each lot purchased - one of each polarity. *** Please be careful when assembling. ***