The seven inch pot is 7 inches wide at the top and has a quarter inch rim around it. This makes the opening 6.25 inches. It is 7 inches tall and tapers to a 5 inch base.
It is made of sturdy, translucent plastic that allows light to get to your orchid's roots. This is very helpful for most epiphytic orchids that are used to having their roots exposed in their native habitat (in trees). This would include Phalaenopsis, Cattleya, Dendrobium and many other. Phragmepedium, Paphiopedilums, being ground dwelling terrestrial orchids, should have opaque pots.