Mainly made up of N52 neodymium magnet and a steel shell, it can concentrate the magnetic field on the bottom of magnet which increase the magnetic force by 2.5-4 times compared to the naked magnet . The steel cup can prevent the naked magnet from scratch and chipping during grabbing and clamping. It is designed for heavy duty and underwater use and helps to recover lost equipment, tools, fishing tackles and other ferrous objects in deep water, wells, holes. It is also great for magnet lifting, hanging applications. Specification 1. Material: Neodymium Magnet N52+A3 Steel+Black Resin 2. Magnet Size: Diameter 2.36''*Height 2.26''(Including eyebolt , thickness of magnet base : 0.79'') 3. Rope Size:Diameter 0.4'' *Length 32 Foot 4. Vertical Pull-force: 440 lb Horizontal Pull-force: based on 1.18" Thick Steel Plate 5. Max Working Temperature:80℃ 6. Package Includes: One fishing magnet+ one M8 eyebolt + One locking carabiner + 32 Foot high strength durabale Nylone Rope. Note: 1.The magnetic force 440lb is vertical pull-force which make the magnet pull way from the thick 1.18" steel plate of a tensile tester under ideal condition. The actual pull force will vary mainly depending on the following variables: A: Steel thickness (The thicker the steel is, the stronger the pull force) B: Pulling direction (The smaller the angle taking 90° as a standard, the stronger the pull force), the Pull force in horizontal direction is only about one third of that in vertical direction) C: Attracting position (The farther beyond the center of gravity of the attracted object, the lower the pull force)