These do not have a suction cup and are meant to sit flat on your aquarium substrate.
Plant flats are great for rhizome plants such as Anubias or Bucephelandra (buce) as you can tie the rhizome to the flat and set it right on your substrate. The substrate will not bury and rot your rhizome, but it allows the roots to dig in the the nutrient rich soil and really take off. These Plant Flats are also great, as always, to propagate aquatic mosses, especially moss that likes to grow on the ground.
These Plant Flats are 2" by 2" square, and are printed in aquarium safe PLA filament.