It is the parts there is including a kit with 1 side radiator, and to connect to your old rear radiator, the tube between the radiator only fit together with the latest type of seat mount, the side radiator fits all kart from after 1997 with the new type of fiber glass, there can be some problem with mounting the front clamp to tube on chassis from before 1997,

If you click on the underlined text can you see photos of the parts. 

Number Description Qty. Unit prices  Total
1734 Side pod for side radiator, available in Red, Yellow, Black and white 1    
4066 Alum. Radiator 215x450 core 32 mm. 1    
1303 Bolt M6x10 with tube 2    
1631 Rubber bush 8/17/23,5x19 3    
1301 Bolt with tube M8x25 with tube 1    
1304 Pin to diagonal tube 8x52 1    
1294 Diagonal tube 10x260 to side radiator 1    
1650 Rubber damper M6/20x20 1    
1603 Alum. pin 8/M8x54  1    
1640 Rubber bush 8/16x8 1    
1604 Alum. pin 8/M8x68 1    
1641 Rubber bush 8/16x20  1    
1308 Bracket to side radiator 2,5x20x76 4    
4079 Tube with expansion cap 1    
1614 Alum. tube 20/22x960 from radiator to radiator  1    
1615 or 1616 Alum. tube from side radiator to motor 1    
1248 Tube 22 with tube 8 for air in side radiator 1    
4097 water hose clip 19-28 6    
4040 R- clip 2 3    
6042

Radiator kit with 1 radiator for Rotax 257 

     
         
4176 Rubber bend 90 22 1    
6043 Radiator kit with 1 Radiator for Rotax 256       
  The bracket for the chassis is not the right one if the side radiator is made after 2003, please see new bracket