Making a starter with a stir plate? Most likely, you are using a stir bar to mix things up...and nobody wants to toss the stir bar in with their beer! That's where this handy retrieval magnet comes into play. This is a powerful magnet which can attach to the stir bar through the glass walls of an Erlenmeyer flask or growler, allowing you to retrieve the magnet before pouring your starter into the fermenter. A functional piece of equipment for any stir bar owner!