WBX-MS Weatherproof Electric Box for Outdoors, 345 X 220 X 126.5 Mm, Grey

The weatherproof box also has five cable outlets with two optional M20 gland points. WITH A HINGED FRONT COVER, A SECURE SIDE CATCH: The outdoor weatherproof box also has wall fixing capabilities as well as a hook and fastener strip to hold the extension lead in place.

eBay