From Makers Electronics's description

UNI-T UT121B Smart Digital Multimeters UT121 series feature large-screen & ultra-thin multimeters and auto range and they can display two measurement results at the same time, which is convenient for home and non-professional users. They are convenient and fast electronic tools. Features True RMS. AC 750V/DC 1000V voltage measurement. 60MΩ large resistance measurement. 60mF large capacitance measurement. Full-scale input protection. NCV/LIVE measurement. Large size LCD screen. 19mm ultra-thin body. 6000 counts. Intelligent identification gear. Specifications Specifications Range UT121B AC voltage (V): 6.000V/60.00V/600.0V/750.0V ±(1.5%+3) AC voltage frequency (Hz): 10Hz-1kHz ±(0.5%+2) DC voltage (V): 6.000V/60.00V/600.0V/1000.0V ±(1.2%+3) Resistance (Ω): 600.0Ω/6.000KΩ/60.00KΩ/600.0KΩ/60.00MΩ ±(2%+5) Capacitance (F): 60.00nF/600.0nF～600.0μF/6000uF～60.0mF ±(10%+5) Frequency (Hz): 10.00Hz-10.00MHz ±(0.1%+3) Temperature(℃/℉): –40℃～1000℃/–40°F～1832°F ±3℃/±6℉ Features Display count: 6099 Dual display: √ Auto range: √ NCV detection: √ LIVE detection: √ Diode test: √ Continuity buzzer: √ LCD high voltage alert: √ Flashlight: √ Low battery indication: √ Auto power off: √ Data hold: √ Category ratings: CATⅢ 600V General Characteristics Power: 2 x AAA Battery 1.5V Display: 52mm x 66mm Product size: 143mm x74mm x 17mm Product net weight: 142g Applications Electrical Testing. Voltage and Current Measurement. Resistance Testing. Continuity Checking. Automotive Diagnostics. Package Contents 1 x UNI-T UT121B Smart Digital Multimeter 2 x AAA Battery 1.5V (Included in UT121B Digital Multimeter Unit) 1 Pair x Test Lead 1 x K-Type Temperature Probe 1 x User Manual 1 x Carrying Bag Documents Datasheet User Manual-English

From Most Electronic's description

Smart Digital Voltmeter / Multimeter UNI-T ( UT121B ) is a high-quality electronic component designed for Arduino, prototyping, and educational electronics. UT121 series feature large-screen & ultra-thin multimeters and auto range and they can display two measurement results at the same time, which is convenient for home and non-professional users. They are convenient and fast electronic tools. Features True RMS AC 750V/DC 1000V voltage measurement 60MΩ large resistance measurement 60mF large capacitance measurement Full-scale input protection NCV/LIVE measurement Large-size LCD screen 19mm ultra-thin body 6000counts Intelligent identification gear Specifications Range UT121B AC voltage (V) 6.000V/60.00V/600.0V/750.0V ±(1.5%+3) AC voltage frequency (Hz) 10Hz-1kHz ±(0.5%+2) DC voltage (V) 6.000V/60.00V/600.0V/1000.0V ±(1.2%+3) Resistance (Ω) 600.0Ω/6.000KΩ/60.00KΩ/600.0KΩ/60.00MΩ ±(2%+5) Capacitance (F) 60.00nF/600.0nF～600.0μF/6000uF～60.0mF ±(10%+5) Frequency (Hz) 10.00Hz-10.00MHz ±(0.1%+3) Temperature(℃/℉) –40℃～1000℃/–40°F～1832°F ±3℃/±6℉ Features Display count6099 Dual display√ Auto range√ NCV detection√ LIVE detection√ Diode test√ Continuity buzzer√ LCD high voltage alert√ Flashlight√ Low battery indication√ Auto power off√ Data hold √ Category ratings CATⅢ 600V General Characteristics Standard accessories UT121B Batteries, test leads, temperature probe, English manual Power 2*1.5V AAA Display UT121A/UT122B: 52*66mm; UT122: 65*55mm Product size UT121A/UT122B: 143*74*17mm; UT122: 144*71*15.5mm It’s perfect for DIY makers, students, and anyone building custom electronic circuits or STEM kits.

From Micro Ohm's description

Features of UT121 Series Smart Digital Multimeters ● True RMS ● AC/DC 600V voltage measurement (UT121A) ● AC 750V/DC 1000V voltage measurement (UT121B) ● 60MΩ large resistance measurement (UT121B) ● 60mF large capacitance measurement (UT121B) ● AC/DC 600V voltage measurement (UT122) ● 60MΩ large resistance measurement (UT122) ● 99mF large capacitance measurement (UT122) ● Built-in rechargeable lithium battery, Type-C charging (UT122) ● Temperature measurement (UT122) ● Full-scale input protection ● NCV/LIVE measurement ● Large size LCD screen ● 19mm ultra-thin body ● 6000counts ● Intelligent identification gear Specifications of UT121 Series Smart Digital Multimeters Specifications Range UT121A UT121B UT122 AC voltage (V) 6.000V/60.00V/600.0V ±(1.0%+3) ±(1.0%+3) 6.000V/60.00V/600.0V/750.0V ±(1.5%+3) AC voltage frequency (Hz) 10Hz-1kHz ±(0.5%+2) ±(0.5%+2) ±(0.5%+2) DC voltage (V) 6.000V/60.00V/600.0V ±(0.7%+3) ±(0.5%+3) 6.000V/60.00V/600.0V/1000.0V ±(1.2%+3) Resistance (Ω) 6000Ω/60.00KΩ/600.0KΩ/6.000MΩ/10.00MΩ ±(2.0%+5) 600.0Ω/6.000KΩ/60.00KΩ/600.0KΩ/60.00MΩ ±(2%+5) 600.0Ω/6.000KΩ/60.00KΩ/600.0KΩ/6.000MΩ/60.00MΩ ±(2.0%+5) Capacitance (F) 60.00nF/600.0nF～600.0μF/6000uF～60.0mF ±(10%+5) 99.99nF/999.9nF～9.999μF/9.999mF～99.99mF 10% Frequency (Hz) 10.00Hz-10.00MHz ±(0.1%+3) ±(0.1%+3) Temperature(℃/℉) –40℃～1000℃/–40°F～1832°F ±3℃/±6℉ ±3℃/±6℉ Features Display count 6099 6099 6199 Dual display √ √ √ Auto range √ √ √ NCV detection √ √ √ LIVE detection √ √ √ Diode test / √ √ Continuity buzzer √ √ √ LCD high voltage alert √ √ √ Flashlight √ √ √ Low battery indication √ √ √ Auto power off √ √ √ Data hold √ √ √ Category ratings CATⅢ 600V CATⅢ 600V CATⅢ 600V General Characteristics Standard accessories UT121A: Batteries, test leads, English manual; UT121B/UT122: Batteries, test leads, temperature probe, English manual Power 2*1.5V AAA Display UT121A/UT122B: 52*66mm; UT122: 65*55mm Product size UT121A/UT122B: 143*74*17mm; UT122: 144*71*15.5mm Product net weight UT121A/UT122B: 142g; UT122: 157g Standard individual packing Gift box, carrying bag