We recommend 1 cartridge for every 12? interval for curved application; 9? interval for straight run. Be sure to include 1 additional cartridge to your total count. If your wall is sharply curved, add additional mounting hardware at every turning point or at point of track connections. This bracket needs to work in conjunction with ceiling mount cartridge CC3 or CC2. Your track system is complete and you are ready to check out once these components have been placed in your shopping cart. To order other optional items, click on “Optional Accessories” before check out.