2 part domical cover for bolt down posts – perforated fencing These domical covers are a no-brainer for any fencing set-up. It adds a much-needed guard and layer of protection to your posts, and also look stylish! This domical cover is designed for use with the 50 x 50mm bolt down posts for our perforated pool fencing. Specifications: It’s time to get technical! Here’s what you need to know. These domical covers come in a two-part design for simple installation. They can be fitted onto a post’s base plate after fence installation. So, you can even buy these covers for fences you’ve had up for years and retrofit them! These covers suit base plates measuring at 135 x 100 millimetres.