AOP Precast produced loop ferrule insert is manufactured by welding a loop strut to a blind end ferrule which have NC thread. Safe Working Load provides a factor of safety of approximately 3 to 1 in 3,000 psi normal weight concrete. Safe Working Loads are based on 1/2" setback from face of concrete. loop ferrule insert is available in the sizes shown in the chart and is well suited for structural connections and the suspension of equipment, piping, etc. Minimum spacing between loop ferrule inserts is twice the minimum corner distance.