Specification:

Size: Ring 37-27.5x3.9 N42
Outer Dia: 37 mm
Inner Dia: 27.5 mm
Thickness: 3.9 mm 
Grade: N42
Coating: Nickle - Ni  
Max Operating Temperature: 80°C   

Description:
Nickel Coated Magnets have many industrial, educational and household uses. These Magnets are highly resistant against demagnetization.