Easy open liners that can be paired with nesting tubes. The liners are removed from the inside of the nesting tubes and then unfurled at the end of the season allowing you to remove and clean the cocoons. Just replace the liners each season. Early in the spring wild mason bees search for nest sites such as this home. Alternately, mason bees can also be bought and placed inside the home. Liners are meant for a one-time use. Once the bee uses the nest, dirt and parasites decreases the livability of the nest. If a liner is not used, it can be set out again the following spring. In the fall (Oct-Dec) unfurl the liners and gather hibernating mason bee cocoons. These can be washed and stored over the winter ready for the following spring. Please note these liners can be used in combination with the chalet or condo kit mason bee houses, or the mason bee nesting trays.