• Optical grade magnifying lens with 4" viewing portal is perfect for aquarium photography with focal range approximately 3 to 8 inches.
• Held in place by strong rare earth magnets for use on tanks up to 5/8" (16mm) tank wall thickness
• Easily moves around the tank for viewing from any location
• Great at checking for any early signs of disease or pests on your reef coral  or fish!
• Deep See is Safe for both glass and acrylic!