I think you meant fully submersible. All aquarium heaters are submersible. That one is not fully submersible. I honestly think that heater is a piece of crap. I have one and it's turned up as high as it can go and it just keeps it at a stable temperature.
55 Gallon-two clown knifefish, chocolate pleco
46 Gallon Bow Front-Planted-swords, java fern and African cichlids, sail fin pleco
29 Gallon-black ghost knifefish, bristlenose pleco
10 gallon-brackish, figure-eight puffer, knight goby