GENUINE IROBOT ROOMBA TOP PLATE FROM IROBOT ROOMBA 535 | eBay
Compatible with Roomba Battery Accessory Ni-MH 3.5 AH Battery and Accessory Part Kit 500 Series 500 510 520 530 531 535 536 540 545 550 a Set of 10 - Walmart.com
Comparison of Roomba 500 Series Robots | Robot Reviews