• The GXL-24 can be used with batteries or AC Adapter, while M24 can only be used with batteries.
  • The GXL-24 shows results directly on a screen while the M24 uses LED lights
  • The M24 can only identify karatage in 2 karat intervals while the GXL-24 can identify in single karat intervals
  • The GXL-24 uses a gel solution which lasts approximately 150 tests while the M24 uses a liquid solution which lasts 50-60 tests
  • Testing refills for the GXL-24 are about $15 while M24 refills are about $27
  • Overall the GXL-24 is better for frequent or professional testers, while the M24 is a better tool for less frequent or personal use