Hide two bars at the top from non-admin users

HI,

I have been trying to hide top 2 bars at the top from non-admin users in sharepoint 2013 using SP:SharePointSecurityTrimmedControl. And this is what I did in the master page

//Code of 2 bars

</SharePoint:SPSecurityTrimmedControl>

So, the admin users are able to view which is working correctly. The  users with contribute permissions are unable to see it which is again perfect. However, any user with read access is able to see the top bars and I'm not sure why it is happening. Is there something wrong with the permissions string i specified. Kindly, check and let me know your suggestions to fix this issue.

Thanks.