The Virtual Halo is a perfect help for homes with pets. Here, a sleeve slides over the Virtual Wall to create a halo-shaped protective zone around pet bowls or other items on the floor that you want Roomba or Scooba 450 to go around while cleaning. The protective zone is approximately 20 inches in diameter. Requires 2 C batteries, not included. Compatible with all Roomba 500, 600, 700 and 800 Series models and Scooba 450.