The BirdieBall Cup and Flag system works in conjunction with all BirdieBall putting greens (both indoor and outdoor), and also works well with other putting greens that are at least 1/2" thick. If you need a replacement cup/flag, or decide that you want more cups and flags in your green down the road, this product is perfect for you. For adding cups to your green, we also offer a hole cutter for purchase, so you can cut more holes after receiving the green. Purchase a hole cutter here Standard Cup + Flag (1/2" deep) 1 Standard Cup + 1 Extraction Flag Cup Depth: 1/2" (works best with Classic Greens and Outdoor Greens) Cup Diameter: 4.25” Flag Height: 11” tall Now available in a Magnetic version for added stability (great for use in high traffic areas or with our outdoor turf mats) High-Back Cup + Flag (1/2" deep with raised lip) 1 Cup and 1 Extraction Flag Cup Depth: 1/2" deep with a 1" raised lip at the back (works best with Classic Greens and Outdoor Greens) Cup Diameter: 4.25” Flag Height: 11” tall Double Depth Cup + Flag (1" deep) 1 Cup and 1 Extraction Flag Cup Depth: 1" deep (works best with Double Depth greens and shims) Cup Diameter: 4.25” Flag Height: 11” tall