The AP12-1-65-203 is a two-pole hydraulic magnetic circuit protector designed for DC applications with short time delay characteristics and a nominal current rating of 20 amperes. This fully sealed unit combines accurate, reliable circuit protection with inverse time delays and trip-free features, maintaining consistent trip current performance across a wide temperature range unlike thermal protectors. The device features a DC series resistance of 0.005 ohms and operates with trip time characteristics ranging from 9 to 60 seconds at 125% rated current, 1.15 to 7 seconds at 200% rated current, and 0.110 to 1 second at 400% rated current. The protector weighs approximately 1.8 ounces (49 grams) per pole and includes an auxiliary switch rated at 3.0 amps at 120 VAC or 50 VDC. This configuration is ideal for applications requiring precise circuit protection in DC power systems, industrial control circuits, and equipment where reliable overload and short-circuit protection with controlled time delays is essential.