A valuable safety tool for range or field. It cannot be locked in place unless the bolt is retracted. Once in place it seals the magazine well and the ejection port door may be closed. From a distance the bright baseplate indicates a safe weapon.FeaturesInsures safe weapon transit to and from the firing range. Prevents dust accumulation in weapons that are stored with the bolts removed. Block cannot be locked in place unless bolt is fully retracted or removed from the weapon.