The EKM 25IDS sounds like it could be the correct meter for you if your wires are under 3/8" diameter and you are metering less than 100 amps.
You do not need to purchase external CTs with this meter. The EKM 25IDS already has the CTs internally. When you pass your wires through the tubes in the meter body, you will be passing them through the internal CTs.
Here is the product page for the EKM 25IDS: https://www.ekmmetering.com/basic-kwh-m ... 25ids.html
Here is the Spec Sheet for the EKM 25IDS: https://documents.ekmmetering.com/EKM-2 ... -Sheet.pdf
Here are the installation instructions (from the spec sheet):
1. Use a volt meter to confirm that you have 240 volts between L1 and L2.
This meter will not function correctly unless this is the case. For 120V
systems, use our EKM-15IDS v.2, EKM-15E, or any Omnimeter model.
2. Disconnect or switch power off before attempting to install, connect,
disconnect, or service the meter. ALL POWER MUST BE TURNED OFF!
3. IMPORTANT: Distinguish and then identify the 2 hot Lines and the
neutral line. Label all 3: L1, L2, N.
4. Once the power has been turned off, pass line 1 and line 2 through the
two holes in the meter. (for a retrofit installation this may first require
disconnecting the ends of L1 and L2 from a breaker or junction box)
5. Once the wires are through the meter, the ends should be reconnected
in their original positions. On the meter, tighten down the tap screws
for each line that passes through the meter. The tap screws penetrate
the wire insulation and power the meter once the power is turned on.
6. Mount the meter using 35mm DIN Rail in a protected indoor location.
If installing outdoors, a UL Listed Type 4 Enclosure is required.
7. Once the above steps are completed, and you are ready, you can turn
the power back on and begin to read your meter.
Here is a photo showing the wires that are being measured passing through the body of the meter: