30 of the Punniest custom metal signs Puns You Can Find
https://milovgvc312.tumblr.com/post/189844252644/15-best-blogs-to-follow-about-custom-metal-signs
Perspex is one of these. Its lightweight and clear form of thermoplastic can resist breaking compared with glass. So, it is actually a substitute for heavier, shatter-inclined glass.