Dimensions: 1/2" Diameter x 7/32" Thick. NOTE: Use our chromed Nail (#5053EN) to attach this magnet to various surfaces. This nail is specifically for this magnet. These ceramic magnetic dots are grade 5, referred as "Ceramic 5" in industry parlance. This is in the middle of the strength range. This magnetic dot is a great choice for smaller toy trains. Some will use this to repair vintage Brio trains!