Casa Geniune Air Filter vs Generic Air Filter

[dos2]

i use Bosch Replacement Filter for over 4 years mas mura sya ng 50-100 % from Oem ,
yung fleetmax na brand ok din naman ang ang filter just replace it often


Oil Filter = every 5,000 kms
Fuel Filter = every 15,000 kms
Air Filter = every 5,000 or 10,000 kms
Aircon Filter = every 20,000 kms

Am just curious how can an item be 100% cheaper? Indi ba zero na amount nun?