A configuration metric for fence panels giving the panel the ability to rack for steep slopes and stairs. Remember to look for short spans of 6 – 7 feet. For example, let’s say, you have 30 foot straight run and it rises/falls 2 feet over the entire length of this run. Well, you do not need Heavy Rackable fence panels here. You can order Standard which gives you up to 6 inches of racking per panel.