From the Manufacturer
Alnico magnets are strong and permanent. They are made of aluminum nickel and cobalt and work under normal conditions and temperatures. They come with removable keepers. This pocket horseshoe alnico magnet is 1 oz size, has a 1-1/4 lb pull. There is 1/4" between poles.
370-1 Features: -Small but powerful magnet.-For retrieving small steel parts and screws from hard-to-get-at places.-0.25'' opening between poles.-1 oz size.-Carded. Dimensions: -1''H x 1.125''W.