Flipper DeepSee Magnetic Viewer. A magnetically attached optical grade magnifier that can be positioned anywhere on your aquarium. The DeepSee Viewer is perfect for aquarium photography and early detection of disease or pests. See detail in your aquarium like never before! DeepSee Viewer 4” (100mm) Suitable for glass or acrylic tanksFor use on tanks with a glass thickness up to 16mmFocal range of approximately 8-20cm Features 3X Optical grade 4” magnifying lensHeld in place by strong rare earth magnets for use on tanks up to 16mm tank wall thicknessEasily moves around the tank for viewing from any locationGreat at checking for any early signs of disease or pestsSafe for both glass and acrylic DeepSee Viewer Nano 3” (75mm) Suitable for glass or acrylic tanksFor use on tanks with a glass thickness up to 10mmFocal range of approxiamtely 5-15cm Features 4X Optical grade 3” magnifying lensHeld in place by strong rare earth magnets for use on tanks up to 10mm tank wall thicknessEasily moves around the tank for viewing from any locationGreat at checking for any early signs of disease or pestsSafe for both glass and acrylicDesigned for Nano Aquariums