A box of 200 System assemblies (water resistant coated cardboard tube (reusable), white paper liner and reusable black end plug). The System is a favorite of Orchard Mason Bee hosts for its ease of maintenance. Our System assemblies offer the highest protection for the Orchard Mason Bee from predators and moisture. Customers have reused the System for many many years, only needing to replace the white paper liner if it was used by the female OMB