The 310 series is a 3 hour fire-rated, industrial grade electric strike designed for extreme heavy duty applications. The all stainless steel construction of this device makes it ideal for high abuse applications that would disable other electric strikes. This industrial grade electric strike is used with cylindrical locks, mortise locks* and mortise exit devices with a 1/2" or 5/8" throw latchbolt (without deadbolt) on single and pairs of doors.