Sometimes simpler is better. Economical magnets in a basic bar shape feature an opposite pole on each end, creating an interesting arc-shaped magnetic field to explore. Ideal for activities that do not require a lot of lifting power. Learn all about magnetic polarity. A great demonstration and experimentation magnet. One alnico bar magnet with North and South poles stamped. Each magnet measures 6" L x .50" W x .25" T. For ages 3+.