If you are using XHTML and there is a closing tag, eg:-
<html>........</html>
You would not use /> at the end, but if there is not a closing tag eg:-
<meta name...... />
Then you would use /> at the end.
Most modern webpages should use XHTML so you should use:-
<title>Galvanized Aircraft Cable - site.com</title>
<meta name="Description" content="Galvanized Aircraft Cable, 7x7 and 7x19, by the foot or on reels." />
<meta name="Keywords" content="Galvanized Aircraft Cable, 7x7 GAC, 7x19 GAC" />
If you are using old school HTML then you should use:-
<title>Galvanized Aircraft Cable - site.com</title>
<meta name="Description" content="Galvanized Aircraft Cable, 7x7 and 7x19, by the foot or on reels.">
<meta name="Keywords" content="Galvanized Aircraft Cable, 7x7 GAC, 7x19 GAC">