Buy Marine Aquarium Fish Tank Protein Skimmer (DG-2516 Hang On Model) at Amazon UK. Boyu Hang on Protein Skimmer Batteries Included, ‎NoThe DG-2516 hang on protein skimmer is designed to be used hanging on the outside of your fish tank, utilising the rim of the tank to grip on to and is suitable I cant complain on the quality of this skimmer, it wasn't the easiest to setup as the instructions aren't really clear so there is a lot of reliance on