Aluminum, made from scratch. I've been using climbing stands for a long time so getting into saddle hunting, I thought I would try to come up with a platform climber I could use with a saddle. It has potential. I'll need to either add a folding post in the center with a versa button to keep it from spinning when I push off the side or just run a strap around the base to hold it tight. Got up on it today and found it comfortable resting my feet on the two uprights that hold the strap like an angled platform.