These moss ledges were printed by Han Tran. Plenty of water can be circulated through these ledges while maintaining a good grip on your moss fronds. There are "teeth" on all sides in which to thread your line through to keep it in place and keep it tight on the fronds. With plenty of venting in the center, it makes it easier to thread the line through for extra security for those shorter pieces as well. These adhere to the tank with two suction cups that is approximately 1.25 inches in diameter so that it is very secure.