The Redmi Note 9S runs MIUI 11 based on Android 10 and packs 64GB of inbuilt storage that can be expanded via microSD card (up to 512GB) with a dedicated slot. The Redmi Note 9S is a dual-SIM (GSM and GSM) smartphone that accepts Nano-SIM and Nano-SIM cards.
Connectivity options on the Redmi Note 9S include Wi-Fi 802.11 a/b/g/n/ac, GPS, Bluetooth v5.00, USB Type-C, Wi-Fi Direct, 3G, and 4G (with support for Band 40 used by some LTE networks in India) with active 4G on both SIM cards. Sensors on the phone include accelerometer, ambient light sensor, compass/ magnetometer, gyroscope, proximity sensor, and fingerprint sensor. The Redmi Note 9S supports face unlock.
The Redmi Note 9S measures 165.70 x 76.60 x 8.80mm (height x width x thickness) and weighs 209.00 grams. It was launched in Aurora Blue, Glacier White, and Interstellar Grey colours.