* Optical grade magnifying lens with 5" viewing portal is perfect for aquarium photography with focal range approximately 3 to 12 inches. * Held in place by strong rare earth magnets for use on tanks up to 3/4" (20mm) 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 shrimp or fish! * Designed for all Tanks. - Freshwater, Saltwater or Dry * DeepSee is Safe for both glass and acrylic!