JRF Series which applies with high accuracy coil winding technology on air core that show precise quality from low current to high current and provide optimizing solution to improve conductor positing error and influence of external magnetic field in energy meter and protection measuring technology industry. As split clip flexible outfit, it is simply installed even at limitary space instead of cutting power line. As major features per series, JRF55 / 80 / 105 are designed for compact split clip type and it shielded on joint clip part to maintain less than 1% error by conductor position. JRF 1 / 2 / 3 are designed as clamp type for easy mobile installation and tighten up durability. JRF 1S / 2S / 3S are designed with optimized shielding technology to block influence of external magnetic field completely from high current. Transducer type as Rogowski and integrator joint device are applied with advanced and optimized integration technology and show high accurate characteristic. Rated current is 250A-6000A and it satisfies with IEC60044-8 0.5 / 1.0 grade and it certifies with security accreditation IEC61010-1, UL61010-1 and EN61010-1 as official document.