This kit comes with the parts needed to upgrade your 450X or 550 batteries to the new plastic box style batteries from the original blue batteries. Husqvarna 450X Automowers and 550 Automowers used the blue batteries up to serial number 1913XXXXX. After that they came standard with these black plastic box style batteries. This kit includes the battery cradle, 5 AH batteries (X2), and battery wiring harnesses (X2) and makes it easy to upgrade to this new style of battery. 
 
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