General description Replacement Parts Dust Bag compatible with iRobot Roomba I3+, I4+, I7, I7+, and S9 vacuum cleaners. These bags are brand new, made of high-strength and environmentally friendly materials, and are easy to install. Technical specifications Material: Cloth Package Contents: 18 x Dust Bags Allowed measurement error: +/- 1-3 cm Usage It is recommended to replace the dust bags every 1-2 months for optimal performance. Other information Note: Light reflection and different displays may cause the color of the item to differ slightly from the actual product.