Modular lids (each one is a square) that usually come in pairs or more, so that a rectangle is formed Each of the square-like covering consisting of two triangular parts, so that it is opened by lifting one of the parts.
The lid is similar to another cap by the same manufacturer
Comment by the user Nick: Mercury Communications is now Vodafone, Mercury was part of Cable and Wireless which was bought by Vodafone for £1 billion in 2012, so the Mercury network is now Vodafone.