GM-550 is an industrial infrard themometer, an ideal tool for long distance measurement. All the functions as here belowing:

test range from -50℃ to 550 ℃, emissivity adjustable,
LAL/HAL, Max/Min/Avg/Dif, Offset
EXTRAL FUNCTIONS:
HOLD
AUTO POWER OFF
BACKLIGHT

Features
Data hold
Max/Min/Avg/Dif
Low/High temp alarm
Offset
Laser target pointer
Backlight
Auto power off
https://rajshreeelectronics.com/product/gm550/