Glass disks for use in flying height testers with superior electrical properties.   

Glass Disks for Flying Height Testers GD-FHT™

Ohara’s GD-FHT are finely polished glass disks used in the testing of magnetic recording heads for Hard Disk Drives. We supply two types of disks, Conventional and Lower Microwaviness (Wa). The Conventional disks are well suited for fly height testing above 0.2 u-inch, while the Lower Wa disks are targeting lower fly height values. GD-FHT disks have better electrical properties than conventional disks and will provide better ESD protection. These disks have excellent mechanical strength and can significantly improve your production yields.


  • Conventional GD-FHT™ disks for > 0.2 u-inch
  • Lower Microwaviness (Wa) GD-FHT disks for < 0.2 u-inch
  • Better ESD protection than BK7
  • More scratch resistant than BK7
  • Extremely smooth super polished surfaces
  • Enables ultra-low fly height testing
  • All form factors available
  • Re-Polishing service available
GD-FHT Properties
GD-FHT Wavelength and Surface Specifications
GD-FHT Special Disk Surface Applications