The Dolphin (Mahi Mahi) Release Ruler provides the estimated weight of Dolphin (Mahi Mahi) based on length. The contrasting color combinations provide easily readable measurements to decrease time for a quick release. Don’t have a scale handy? The Release Ruler is the ruler to measure not only the length of your Dolphin (Mahi Mahi), but also provide the estimated weight based on scientific data for the average sizes of Dolphin (Mahi Mahi). Stop guessing! Use the Release Ruler today. The ruler is a durable PVC coated vinyl which is built to stand up to the toughest fishing conditions.