| Hardware and OS | Lava Z21 | Oppo A3s |
| Operating system | Android v11 | Android 8.1 (Oreo); ColorOS 5.1 |
| Processor | Octa core, 1.6 GHz | Octa-core 1.8 GHz Cortex-A53 |
| Custom UI | Android Go | |
| Chipset | | Qualcomm SDM450 Snapdragon 450 (14 nm) |
| GPU | | Adreno 506 |
| Internal memory | 32 GB | 16 GB, 2 GB RAM |
| External memory | Yes, Up to 256 GB | microSD, up to 256 GB (dedicated slot) |
| RAM | 2 GB | |
| Display | Lava Z21 | Oppo A3s |
| Type | IPS LCD | IPS LCD |
| Size | 5.0 inches (12.7 cm) | 6.2" inc |
| Resolution | | 720 x 1520 px |
| PPI /points per inch/ | 196 ppi | |
| Touchscreen | Yes, Capacitive Touchscreen, Multi-touch | capacitive touchscreen |
| Screen-to-Body Ratio | | 81.2% |
| Display area | | 95.9 cm2 |
| Display aspect ratio | | 19:9 (height:width) |
| Pixel Density | | 271 PPI |
| Colors | | 16M |
| Connectivity | Lava Z21 | Oppo A3s |
| 4G Bands | TD-LTE 2300(band 40) / 2500(band 41), FD-LTE 2100(band 1) / 1800(band 3) / 900(band 8) / 850(band 5) | |
| Network Support | 4G, 3G, 2G | |
| NFC | No | |
| SIM Slot(s) | Dual SIM, GSM GSM, Dual VoLTE | |
| 2G Network | | GSM 850 / 900 / 1800 / 1900 - SIM 1 & SIM 2 |
| 3G Network | | HSDPA 850 / 900 / 2100 |
| 4G Network | | LTE |
| USB Connectivity | Mass storage device, USB charging, microUSB 2.0 | |
| VoLTE | Yes | |
| Wi-Fi | Yes, Wi-Fi 802.11, ac/b/g/n | Wi-Fi 802.11 b/g/n, WiFi Direct, hotspot |
| Network | | GSM / HSPA / LTE |
| SIM card | SIM1: Nano, SIM2: Nano | Dual SIM (Nano-SIM, dual stand-by) |
| Bluetooth | Yes, v4.2 | 4.2, A2DP, LE |
| Edge | | Yes |
| GPRS | | Yes |
| GPS | Yes with A-GPS | Yes, with A-GPS |
| Speed | | HSPA 42.2/5.76 Mbps, LTE-A (2CA) Cat6 300/50 Mbps |
| USB | | microUSB 2.0, USB On-The-Go |
| Camera | Lava Z21 | Oppo A3s |
| Camera Setup | Single | |
| Camera Features | Digital Zoom | |
| Flash | Yes, LED Flash | |
| Image Resolution | 2592 x 1944 Pixels | |
| Video Recording | 1280x720 @ 30 fps | |
| Main camera | 5 MP, Primary Camera, | 13 MP, Dual |
| Specs | | 13 MP, f/2.2, AF
-2 MP, f/2.4, depth sensor |
| Features | | LED flash, HDR, panorama |
| Video | | 1080p@30fps |
| Selfie camera | 2 MP, Primary Camera, | 8 MP, Single |
| Multimedia | Lava Z21 | Oppo A3s |
| Headphone jack | 3.5 mm | |
| FM Radio | Yes | |
| Loudspeaker | Yes | |
| 3.5 mm Jack | | Yes |
| Radio | | FM radio |
| Design | Lava Z21 | Oppo A3s |
| Colours | Blue, Cyan | |
| Width | 73 mm | |
| Height | 146.5 mm | |
| Colors | | Red, Dark Purple |
| Thickness | 10.4 mm | |
| Dimensions | | 156.2 x 75.6 x 8.2 mm |
| Weight | 187 grams | 168 g |
| Battery | Lava Z21 | Oppo A3s |
| Capacity | 3100 mAh | |
| Battery capacity | | 4230 mAh, Non-removable Li-Ion |
| Type | Li-ion | |
| Removable | Yes | |
| USB Type-C | No | |
| Standby time | Up to 520 Hours(2G) | |
| TalkTime | Up to 23 Hours(4G) | |
| Other | Lava Z21 | Oppo A3s |
| Release date | | 2018, July |
| Sensors | | Accelerometer, proximity, compass |
| Other features | Lava Z21 | Oppo A3s |
| Fingerprint Sensor | No | |
| Other Sensors | Proximity sensor, Accelerometer | |
