Expires

If Cache-Control isn't present, but the Expires header is

the Expires header value sets the TTL of the associated object
ExpiresByType image/png "access plus 6 seconds"
ExpiresByType image/jpg "access plus 6 seconds"
ExpiresByType image/png "access plus 6 seconds"
ExpiresByType text/x-javascript "access plus 6 seconds"

ExpiresByType image/jpeg "access plus 7 seconds"
ExpiresByType text/css "access plus 7 seconds"
ExpiresByType application/x-shockwave-flash "access plus 7 seconds"
ExpiresDefault "access plus 7 seconds"

ExpiresByType image/gif "access plus 8 seconds"
ExpiresByType application/pdf "access plus 8 seconds"
ExpiresByType image/x-icon "access plus 8 seconds"