Add more valuable bee pollinators to your garden using Replacement Mason Bee Fiberboard Nesting Tubes for Mason Bee Shelter. Contains 94 tubes constructed of fiberboard. They are called Masons because they work with mud to build and seal their nests, as pollinators, Mason Bees are attracted to flowering plants, such as vegetables, fruit trees & bushes, flowering annuals, perennials and vine plants. Their work in the Spring can determine the volume of fruit or vegetables that will be available to harvest. Mount the house to a post or wall ideally near a source of mud.