The OPPO A31 is a budget smartphone with a 6.5 inch HD+ display, 128GB of storage, and 6GB of RAM. It is powered by a MediaTek Helio P35 Octa core processor and runs on Android 10 with ColorOS 7.2. The device has a triple camera setup on the back, consisting of a 12 megapixel main camera, a 2 megapixel depth sensor, and a 2 megapixel macro lens. On the front, it has an 8 megapixel selfie camera.

One of the standout features of the OPPO A31 is its large, 6.5 inch HD+ display, which offers good viewing angles and vivid colors. The display also has a waterdrop-style notch at the top, which houses the front-facing camera. The device has a slim, lightweight design and is available in two color options: Fantasy White and Mystery Black.

In terms of performance, the OPPO A31 is equipped with a MediaTek Helio P35 processor and 6GB of RAM, which should provide smooth and lag-free performance for most tasks. The device also comes with 128GB of storage, which can be expanded via a microSD card. It runs on Android 10 with ColorOS 7.2, which offers a clean and intuitive user interface.

The OPPO A31 has a triple camera setup on the back, which includes a 12 megapixel main camera, a 2 megapixel depth sensor, and a 2 megapixel macro lens. The main camera is capable of capturing good quality photos in well-lit conditions, with good detail and accurate colors. The depth sensor helps in capturing photos with a bokeh effect, while the macro lens allows you to get up close and personal with your subjects. On the front, the OPPO A31 has an 8 megapixel selfie camera, which should be more than sufficient for most users.

The OPPO A31 is equipped with a large 4,230mAh battery, which should provide good battery life for most users. It also supports fast charging, so you can quickly top up the battery when needed. The device also comes with a rear-mounted fingerprint sensor for added security.

In terms of connectivity, the OPPO A31 supports 4G LTE, Wi-Fi, Bluetooth, and GPS. It also has a 3.5mm headphone jack, which is a rarity on modern smartphones.

Overall, the OPPO A31 is a good budget smartphone that offers good performance, a large display, and a decent camera setup. It is currently available in India for a price of around Rs. 11,990. If you are in the market for a budget smartphone, the OPPO A31 is definitely worth considering.