Screen size
K42Winner: 6.6"+0.8%
K51S6.6"
Quick verdict
K51S leads the measured specs 5-3.
Measured wins
K42
3
spec wins
Ties
10
equal specs
K51S
5
spec wins
Overall winner
Screen size
Technology
K42
GSM / HSPA / LTE
K51S
GSM / HSPA / LTE
2G bands
K42
GSM 850 / 900 / 1800 / 1900
K51S
GSM 850 / 900 / 1800 / 1900
3G bands
K42
HSDPA 850 / 900 / 1900 / 2100
K51S
HSDPA 850 / 900 / 1900 / 2100
4G bands
K42
1, 3, 7, 8, 20, 28, 38 - Europe, 1, 3, 5, 7, 8, 20, 28, 38, 39, 40, 41 - Australia
Resolution
equal specsRefresh rate
Peak brightness
Pixel density
CPU speed
RAM
equal specsStorage
equal specsMain camera
Front camera
Battery
equal specsWired charging
Weight
Thickness
IP rating
Wi‑Fi
Bluetooth
equal specsUSB
equal specs5G support
equal specsNFC
equal specs3.5mm jack
equal specsSD card
equal specsStereo speakers
K51S
1, 3, 7, 8, 20, 28, 38
Speed
K42
Yes, 384 kbps
K51S
HSPA 42.2/5.76 Mbps, LTE (2CA) Cat6 300/50 Mbps
Announced
K42
2020, September 21. Released 2020, September 21
K51S
2020, February 18. Released 2020, April 27
Status
K42
Discontinued
K51S
Discontinued
Dimensions
K42
165 x 76.7 x 8.4 mm (6.50 x 3.02 x 0.33 in)
K51S
165.2 x 76.7 x 8.3 mm (6.50 x 3.02 x 0.33 in)
Weight
K42
182 g (6.42 oz)
K51S
194.5 g (6.88 oz)
SIM
K42
Nano-SIM + Nano-SIM
K51S
· Nano-SIM· Nano-SIM + Nano-SIM
Other
K42
MIL-STD-810G compliant* *does not guarantee ruggedness or use in extreme conditions
K51S
MIL-STD-810G compliant* *does not guarantee ruggedness or use in extreme conditions
Type
K42
IPS LCD
K51S
IPS LCD
Size
K42
6.6 inches, 105.2 cm2 (~83.1% screen-to-body ratio)
K51S
6.55 inches, 93.6 cm2 (~73.8% screen-to-body ratio)
Resolution
K42
720 x 1600 pixels, 20:9 ratio (~266 ppi density)
K51S
720 x 1600 pixels, 20:9 ratio (~282 ppi density)
Protection
K42
-
K51S
Scratch-resistant glass
OS
K42
Android 10, upgradable to Android 11
K51S
Android 9.0 (Pie)
Chipset
K42
Mediatek MT6762 Helio P22 (12 nm)
K51S
Mediatek MT6765 Helio P35 (12 nm)
CPU
K42
Octa-core 2.0 GHz Cortex-A53
K51S
Octa-core (4x2.3 GHz Cortex-A53 & 4x1.8 GHz Cortex-A53)
GPU
K42
PowerVR GE8320
K51S
PowerVR GE8320
Card slot
K42
microSDXC
K51S
microSDXC (dedicated slot)
Internal
K42
64GB 3GB RAM
K51S
64GB 3GB RAM
Other
K42
eMMC 5.1
K51S
eMMC 5.1
Quad
K42
13 MP, 27mm (wide), 1/3.1", 1.12µm, PDAF 5 MP, f/2.2, 115˚ (ultrawide), 1/5.0", 1.12µm 2 MP (macro) Auxiliary lens
K51S
32 MP, (wide), PDAF 5 MP, f/2.2, 115˚, (ultrawide) 2 MP (macro) Auxiliary lens
Features
K42
LED flash, panorama, HDR
K51S
LED flash, panorama, HDR
Video
K42
1080p@30fps
K51S
1080p@30fps
Single
K42
8 MP, (wide)
K51S
13 MP, 1/3.1", 1.12µm
Video
K42
1080p@30fps
K51S
1080p@30fps
Loudspeaker
K42
Yes
K51S
Yes
3.5mm jack
K42
Yes
K51S
Yes
WLAN
K42
Wi-Fi 802.11 b/g/n, Wi-Fi Direct
K51S
Wi-Fi 802.11 a/b/g/n, Wi-Fi Direct, DLNAorWi-Fi 802.11 b/g/n, Wi-Fi Direct, DLNA
Bluetooth
K42
5.0, A2DP, LE
K51S
5.0, A2DP, LE
Positioning
K42
GPS
K51S
GPS
NFC
K42
Yes (market/region dependent)
K51S
Yes
Radio
K42
No
K51S
No
USB
K42
USB Type-C 2.0, OTG
K51S
USB Type-C 2.0, OTG
Sensors
K42
Fingerprint (side-mounted), accelerometer, proximity, compass
K51S
Fingerprint (rear-mounted), accelerometer, proximity, compass
Type
K42
Li-Po 4000 mAh
K51S
Li-Po 4000 mAh
Charging
K42
10W wired
K51S
-
Colors
K42
Gray, Green
K51S
Titanium, Pink, Blue, Red
Models
K42
LMK420, LM-K420, LMK420H, LM-K420H, LMK420E, LM-K420E, LMK420Y, LM-K420Y
K51S
LMK510EMW, LM-K510EMW, LM-K510
Price
K42
About 140 EUR
K51S
About 200 EUR