The Halibut Release Ruler provides the estimated weight of Halibut 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 Halibut, but also provide the estimated weight based on scientific data for the average sizes of Halibut. 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.