Eclipse Magnetics E650 Ferrite Red Channel Magnet, 42 lb. Pull Capacity, 4" Length x  1" Width x 9/16" Height Low profile steel channels with ferrite (ceramic) magnets 4" Length x 1" Height x 9/16" Width Max temperature: 176-Degree F Plain fixing holes: 0.281", all painted steel channel magnets are 1" wide Shallow limpet type magnets set in a mild steel shell