The Klein Tools CL312 is a 400A AC True RMS auto-ranging HVAC clamp meter rated CAT III 600V. It measures AC current via the 1.12-inch jaw, plus AC/DC voltage, resistance, continuity, capacitance, DC microamps, and temperature via K-type thermocouple probe. A 4000-count backlit LCD provides clear readings. DC microamps measurement supports flame sensor testing common in HVAC service work. Frequency range extends to 1 MHz. Auto power-off at 15 minutes conserves battery life. Drop-rated to 3.3 feet. Designed for HVAC technicians. Covered by Klein Tools' 1-year limited warranty.
Is the CL312 still available?
No — the CL312 has been discontinued. The CL490 is its primary current-generation equivalent.
What was the CL312 designed for?
The CL312 was a 400A True RMS clamp meter with thermocouple temperature measurement, marketed specifically for HVAC diagnostics. It combined AC current measurement with temperature sensing in a single instrument.
What current model replaces it?
The CL490 (400A AC/DC True RMS, temperature, dual display) is the current equivalent — it adds DC current measurement and a dual-display for simultaneous readings, both useful for HVAC work.
# Klein Tools® CL312 HVAC Digital AC Auto-Ranging Clamp Meter, 400A with Temp **Model:** `CL312` **Brand:** Klein Tools **Category:** Clamp Meter > The Klein Tools CL312 is a 400A AC True RMS auto-ranging HVAC clamp meter rated CAT III 600V. It measures AC current via the 1.12-inch jaw, plus AC/DC voltage, resistance, continuity, capacitance, DC microamps, and temperature via K-type thermocouple probe. A 4000-count backlit LCD provides clear readings. DC microamps measurement supports flame sensor testing common in HVAC service work. Frequency range extends to 1 MHz. Auto power-off at 15 minutes conserves battery life. Drop-rated to 3.3 feet. Designed for HVAC technicians. Covered by Klein Tools' 1-year limited warranty. ## Specifications | Attribute | Value | |---|---| | Product Type | Digital Clamp Meter | | Form Factor | hook | | Ac Amp Capacity | 400 | | True Rms | Yes | | Auto Ranging | Yes | | Temperature Measurement | Yes | | Differential Temperature | No | | Low Impedance Loz | No | | Worklight | No | | Flexible Clamp | No | | Dual Display | No | | Jaw Opening In | 1.12 | | Voltage Range Ac | 600V AC | | Voltage Range Dc | 600V DC | | Frequency Hz | 10 Hz - 1 MHz | | Cat Rating | CAT III 600V | | Battery Type | 3 x AAA | | Overall Length In | 8.7 | | Barcode (UPC) | 092644691379 | | Warranty | 1-year limited | ## What's Included - Carrying Case - Test Leads - Thermocouple - Batteries Source: https://www.jaspecs.com/klein-tools/clamp-meter/cl312-klein-tools-clamp-meter-hvac-digital-ac-auto-ranging-tester-400-amp-temp/