The diameter of entry port is 10mm that perfect to seal 14/16/18 gauge cord, braided cable and flat wire. Designed to keep cord connection secure and protected. Compact size and light weight are great to protect outlet/plug/socket/connection hanging in the air. snap-lock lid, and rubber gaskets, this outdoor Extension box is IP44 waterproof. Made with heavy-duty reinforced PP material to withstand rain, snow, water, dust, dirt and more, continuously protecting outdoor connections from electrical hazard. Easy to use, place the connection into the safety seal enclosure and clip the cord with the clamps. To hang the cover, use the included cable ties and insert them to the side mounting holes. Ideal for a wide range of outdoor & indoor applications including lawn and tools, Christmas holiday lighting, landscape decorations, pool pumps, fountains, fish ponds, patio heaters, air conditioners, security cameras and more. size: 21x7x7cm Colour:black Material:PP Note: This Extension cable box cannot fit for power strip, right-angle plug and large adapter. Package Contents: 2 x Extension cable Plug Connection Protective Safety Cover Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.