Astralpool Base drain for swimming pools for collective use UNI-EN 13451 300x300 resin and fiberglass structure and stainless steel grid. Suitable for pool with liner or concrete. Optional hydrostatic valve. The minimum distance for the installation of the drains must be> 2 m for pools with a collective one and> 1 m for pools for residential use. Available in sizes 300x300 with a diameter of 75 mm or 110 mm.