Instruction: Given a question and the related document, predict if the question is answerable based on the information provided in the document. Output only yes or no.

Input:
Question: Can this be used on concrete walls?
Document: They work so good I bought a bunch more for the future. I compared these to the OOK Hangman and the Interlocking Flushmount. These are much better for earthquake (or casual theft) protection. You have to be pretty careful locating the bottom screw (the instructions sort of work), but there's a little leeway. They're strong, too. I used them to mount heavy pictures. Once you've got the pictures up, they're not going anywhere - even when the big one hits.
This product is easy to install and prevents anyone from walking away with your valuable art. Remember that it is only as strong as the wall you attach it to. If someone wants it, they'll get it. By using this hardware, it makes it a little harder to take. The paintings I installed with this are still on the wall in a public area so I believe that it does the job.
This kit is exactly what I was looking for to secure pictures at our rental cabin. It allows us some piece of mind.
Answer: no