| Hardware and OS | Gretel S55 | Oppo A3s |
| Operating system | Android 7.0 Nougat | Android 8.1 (Oreo); ColorOS 5.1 |
| Processor | Quad-Core (4x Cortex A7 1.5 GHz) | Octa-core 1.8 GHz Cortex-A53 |
| Chipset | Mediatek MT6580A (28 nm) | Qualcomm SDM450 Snapdragon 450 (14 nm) |
| GPU | ARM Mali-400 MP1 | Adreno 506 |
| Internal memory | 1GB 16GB, 1GB · 16GB | 16 GB, 2 GB RAM |
| External memory | | microSD, up to 256 GB (dedicated slot) |
| Display | Gretel S55 | Oppo A3s |
| Type | LCD IPS | IPS LCD |
| Size | 5.5" inc | 6.2" inc |
| Resolution | 720 x 1280 px | 720 x 1520 px |
| Display colors | 16M | |
| Touchscreen | capacitive touchscreen | capacitive touchscreen |
| Screen area | cm2 | |
| Screen-to-Body Ratio | | 81.2% |
| Screen format | 16:9 (height:width) | |
| Display area | | 95.9 cm2 |
| Screen to body ratio | 70% | |
| Display aspect ratio | | 19:9 (height:width) |
| PPI /points per inch/ | 267 PPI | |
| Pixel Density | | 271 PPI |
| Screen protection | Scratch resistant | |
| Colors | | 16M |
| Connectivity | Gretel S55 | Oppo A3s |
| 2G Network | | GSM 850 / 900 / 1800 / 1900 - SIM 1 & SIM 2 |
| 3G Network | | HSDPA 850 / 900 / 2100 |
| 4G Network | | LTE |
| NFC | No | |
| Wi-Fi | 802.11b, 802.11g, 802.11n,Wi-Fi Hotspot | Wi-Fi 802.11 b/g/n, WiFi Direct, hotspot |
| Network | 2G / 3G / | GSM / HSPA / LTE |
| SIM card | Dual SIM, dual stand-by (Micro SIM Micro SIM) | Dual SIM (Nano-SIM, dual stand-by) |
| Bluetooth | Bluetooth 4.0, A2DP | 4.2, A2DP, LE |
| Edge | Yes | Yes |
| GPRS | Yes | Yes |
| GPS | GPS, A-GPS | Yes, with A-GPS |
| Speed | | HSPA 42.2/5.76 Mbps, LTE-A (2CA) Cat6 300/50 Mbps |
| USB | Yes | microUSB 2.0, USB On-The-Go |
| Camera | Gretel S55 | Oppo A3s |
| Rear camera, main | 8 MP, Single | |
| Camera specs | 8 MP, ?/ 2.2, (wide), 1.12 µm | |
| Main camera | | 13 MP, Dual |
| Functions | LED flash | |
| Specs | | 13 MP, f/2.2, AF
-2 MP, f/2.4, depth sensor |
| Features | | LED flash, HDR, panorama |
| Front camera, selfie | 4 MP, Single | |
| Video | 1080p video | 1080p@30fps |
| Specifications | 4,9 MP, ?/ | |
| Selfie camera | | 8 MP, Single |
| Multimedia | Gretel S55 | Oppo A3s |
| Headphone jack | Yes | |
| 3.5 mm Jack | | Yes |
| Radio | Yes | FM radio |
| Design | Gretel S55 | Oppo A3s |
| Dimensions (HxWxD) | 153.3 x77.2 x 8.7 mm | 6.04 x 3.04 x 0.34 in | |
| Colors | Black, Blue, Gold, Red | Red, Dark Purple |
| Dimensions | | 156.2 x 75.6 x 8.2 mm |
| Body build | Plastic | |
| Weight | 174 g | 6.14 oz | 168 g |
| Battery | Gretel S55 | Oppo A3s |
| Battery | 2600 mAh, Li-Ion, Removable | |
| Battery capacity | | 4230 mAh, Non-removable Li-Ion |
| Other features | Gretel S55 | Oppo A3s |
| Sensors | Fingerprint (rear-mounted), Proximity, Accelerometer , Infrared port | |
| Other | Gretel S55 | Oppo A3s |
| Release date | | 2018, July |
| Sensors | | Accelerometer, proximity, compass |
