The INKBIRDPLUS Portable CO2 Detector (model PTH-10C) is a compact indoor air quality monitor designed for continuous carbon dioxide measurement in residential, office, and travel settings. At its core, the device employs a nondispersive infrared (NDIR) sensor, a mature technology known for long-term stability and selectivity to CO2, avoiding the drift common with chemical sensors. The sensor detects CO2 concentrations ranging from 0 to 9999 ppm with a resolution of 1 ppm, providing real‑time feedback through a full‑color LCD display that changes hue according to detected levels—green for normal, yellow for moderate, and red for elevated. This visual cue allows users to quickly assess air freshness at a glance.

The outer casing is constructed from matte ABS plastic, chosen for its durability and lightweight portability. Measuring just 2.8 x 1.4 x 4.1 inches and weighing under 100 grams, the detector fits easily into a pocket or bag, making it suitable for monitoring air quality during commuting, hotel stays, or shared workspaces. The LCD screen measures 1.77 inches diagonally with a resolution of 128x160 pixels, offering clear readability even under moderate ambient light. A single button powers the unit and cycles through display modes, keeping operation straightforward.

The device runs on a built‑in rechargeable lithium‑ion battery (200 mAh) that provides up to 8 hours of continuous use on a full charge; recharging is accomplished via a standard USB Type‑C port, ensuring compatibility with most chargers and power banks. Performance consistency is supported by automatic baseline calibration (ABC) logic, which periodically adjusts the sensor reading to 400 ppm (fresh outdoor air level) when exposure to low CO2 periods occurs. This feature maintains accuracy over extended use without manual recalibration. The response time (T90) is under 10 seconds for a change of 500 ppm, allowing users to see fluctuations in air quality promptly.

The detector operates across a temperature range of 0°C to 50°C and humidity of 0% to 95% RH (non‑condensing), covering typical indoor conditions. No moving parts or consumable filters are required, reducing long‑term maintenance. Practical applications include helping users identify when to ventilate rooms to avoid drowsiness or stuffiness, particularly in sealed offices, bedrooms, or classrooms. The compact size also makes it a convenient travel companion for checking hotel room ventilation.

The unit emits no noise during operation, and the display can be dimmed in low‑light settings by a short press of the button, avoiding disturbance at night. Pricing places this unit at a very affordable level for its feature set, offering a cost‑effective entry into personal CO2 monitoring without sacrificing essential accuracy and portability. The design emphasizes straightforward functionality without unnecessary extra sensors, keeping the focus on the single most important indoor air parameter for cognitive performance and well‑being.