The quality of durability is the first one.

• 
  LRM-150W-B LRM-300W-B LRM-500W-B LRM-600W-B
• 
  LRM-300W-C LRM-500W-C LRM-600W-C
• 
  LRM-800W-B LRM-1000W-B LRM-1200W-B
• 
  LRM-800W-C LRM-1000W-C
• 
  LRM-1500W-B LRM-2000W-B
• 
  LRM-2500W-B LRM-3000W-B
• 
  LRM-4000W-B LRM-5000W-B LRM-6000W-B