One side with 3M self - adhesive If you could not find what you want, please just leave us a message or email us.We are professional magnetic material supplier. We have more than one hundred different sizes magnets in stock. We could produce as per your design for bulk quantity. Condition: Brand new Shape: Disc 3M adhesive thickness 0.3mm magnet size : 18mmx1mm 18mmx1.5mm 18mmx2mm Tolerance: +-0.2mm Material: Neodymium magnets Certification:RoHS passed Grade: N35 Magnetization: Axially magnetized / Poles on Flat Ends Max Operating Temperature: 80C/176F Plating: nickel copper nickel triple layer plated Caution: strong magnets are brittle; strong magnet could pinch your fingers badly; if you allow two magnets attract together, it may cracks and the chips could hurt your eyes