It is veneered/ faced with galvanized sheeting.
There is a wood frame and back boards behind the sheeting.

We've used this detail a couple of times. It's a great way to impart an industrial look or just dress up a plain jane wood retainer.

I love that look!

Thank you DD.

Do you sell instructions and what materials are used for this retaining wall

What is the fence above made out of?

Wood. The boards are just aligned horizontally rather than vertically.

I love this and I'm going to be redoing my retaining wall in my backyard. Currently we have ugly cinder block that we'll need to dig out. Any suggestions for how to price the project materials out? What to use for the wall, posts, headers, steps & etc? My father is going to be completing but I would love to have an idea of what he'll need and cost.

Is the cinder block no longer structurally sound? If it is still good, why not use this look as a facing?

There are a number of plans on the web if you do a search for galvanized metal raised beds. Here is one. http://blueberryhillcrafting.com/2013/04/24/how-to-galvanized-garden-beds/