Condition: brand newShape: discDimension: diameter 4mm x thickness 2mmTolerance: +-3mmMaterial: Neodymium MagnetsMagnetization: poles on largest surfacesMax Operating Temperature: 80°C/176°FNOT use to water meter ,gas meter ,electric meter ,it is harmful to your country . and i can not promise to stop any meter deviece.Sometimes one of hundred will be like that surface and side maybe 1-2mm tolerance or Groove . we will be so sorry for it ,but it will be aslo strong ,and not affect to use . so please understand it .it is normal .