What it is and what the ratings mean for fit
The SIDAC 4EP4002-6MS00 is a 3-phase filter reactor — a line reactor — rated for 18 A continuous with a 20 A maximum, on a 460 V AC, 60 Hz system. The 0.0027 H inductance and 5.67 % relative throttling factor tell you it's sized to limit harmonic current and reduce voltage notching from a VFD or other non-linear load. The 12.5 kvar reactive power rating gives the reactive compensation capability at the fundamental frequency. The 252 Hz resonant frequency means it's tuned away from the 5th and 7th harmonics typical of 6-pulse drives, so it won't accidentally amplify those frequencies.
Where it goes and how it connects
IP00 means no enclosure — this is an open-frame reactor intended for mounting inside a panel or cabinet where it's protected from dust and direct contact. The screw-type terminals for the main current circuit accept standard power wiring. Thermal class B (130 °C rise) per IEC 60085 keeps the copper within rating at the 40 °C ambient. The 91 W power loss at rated current needs to be factored into the panel's thermal budget.