According to David Hackl, all of the traps are real objects, and not CGI. They were designed to look horrific but ultimately be safe for the actors in them. Writer Marcus Dunstan said: "It's built to function there on the day", and added: "It works. So if there's a scalping chair — there really was a chair with working gears to grind and pull your scalp back." The most potentially dangerous item was a "water box" used in Saw V, in which one of the actors (Scott Patterson, as Peter Strahm) had to keep his head submerged as long as possible. Another element of the traps is that Hackl desired a specific look of rust and menace, but he also wanted them to have a type of beauty about them.[