Same weights you can buy in hobby shop at only ⅓ the cost. Package is heavy, but weights work perfectly in model building.Weights are steel. Easy to place perfectly by holding them with a small pencil-size magnet.Easy to separate by cutting backing with an x-a to knife. There is a thin plastic tape on the top of each strip that I removed before cutting. Backing paper can be a pain to remove to expose the adhesive but again, an x-acto type knife does the job.