This is cable railing. It can be straight metal or coated. Typically we use 1/4" or 3/16". They are spaced at 3 3/4" apart.

Thank you... i really appreciate this...

You can find more information on cable railing at www.ultra-tec.com. We manufacture cable railing hardware that hides inside the end posts.

Is this type of railing more expensive than a typical wood railing with ballasts?

yes, considerably - but if you want to keep the view open it works really well.