1 ct CMS Magnetics up to 210 LB Holding Power Round Base Magnet RB90 4 7/8" Cup Magnet Strong holding power - up to 210 LB each with direct touch and direct pull on a 20mm thick steel The magnet is protected by steel cup. Good for sign holding Chrome plated steel cup for rust proof Convenient Center Hole for Easy Application Not for fishing purpose but for holding only