The only difference is the price and the weight, as PCM011989 says the fans are included.

Net weight (kg) Dx weighs = 15.3 and DX weighs = 16.8
Pre-installed fans: ModelLIGHT BASE 900 DX | Black LIGHT BASE 900 FX | Black
Fan side - 3x Light Wings Reversed 140mm PWM
Rear fan - 1x Light Wings 140mm PWM
Bottom fan - -
Dimensions (L x W x H), (mm) - 140 x 25 x 140
Speed at 100% PWM / 12V (rpm) - 1500 / 1300
Air volume at 100% (CFM / m3/h) - 56.0 / 95.1 | 51.37 / 87.28
Air pressure at 100% PWM / 12V (mm H2O)- 1.49 / 1.1
Volume at 100% PWM / 12V (dB(A)) - 23.3 / 25.5
Voltage range (V DC) - 5-13.2 / 5-12
Power consumption (W) - 3.8 / 0.72
Rated current (A) - 0.32 / 0.06
Connector plug - 4-pin PWM
Life expectancy at 25 °C (hours) - 60,000
Fan control - 2x 12 ports
Gross weight, packaging (kg) 17.7 18.7
Recommended retail prices vary

Hope I could help...

Greetings
SUCU GmbH Your PC Maker

Fans are supplied with the one