Asus Zenfone 4 Pro ZS551KL vs Celkon A66

Compare recorded specifications, size and practical differences.

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Key differences

Calculated from recorded specifications using minimum difference thresholds. These are differences, not an overall ranking. For three phones, numeric highlights compare the two extremes.

  • Weight

    A66: 77 g lighter

    Zenfone 4 Pro ZS551KL:
    175 g
    A66:
    98 g
  • Width

    A66: 8.4 mm narrower

    Zenfone 4 Pro ZS551KL:
    75.6 mm
    A66:
    67.2 mm
  • Screen diagonal

    A66: 1 in smaller diagonal

    Zenfone 4 Pro ZS551KL:
    5.5 in
    A66:
    4.5 in
  • Rear camera layout

    Zenfone 4 Pro ZS551KL:
    Dual
    A66:
    Single
  • Depth

    Zenfone 4 Pro ZS551KL: 3.4 mm thinner

    Zenfone 4 Pro ZS551KL:
    7.6 mm
    A66:
    11 mm
  • Height

    A66: 20.9 mm shorter

    Zenfone 4 Pro ZS551KL:
    156.9 mm
    A66:
    136 mm

Physical size

Relative size, not calibrated actual size. Front and side outlines share one scale and a bottom baseline. Generic outlines use recorded body dimensions, excluding camera bumps.

  1. 1. Zenfone 4 Pro ZS551KL

    Height:
    156.9 mm +20.9 mm versus A66
    Width:
    75.6 mm +8.4 mm versus A66
    Depth:
    7.6 mm
  2. 2. A66

    Height:
    136 mm
    Width:
    67.2 mm
    Depth:
    11 mm +3.4 mm versus Zenfone 4 Pro ZS551KL

Weight

Bars start at zero and share a scale within this chart.

  1. 1. Zenfone 4 Pro ZS551KL

    175 g

    +77 g versus A66

  2. 2. A66

    98 g

Screen size

Approximate rectangular screens calculated from recorded diagonal and aspect ratio at one relative scale. Rounded corners and cutouts are not subtracted. These are not phone outlines or calibrated actual sizes.

  1. 1. Zenfone 4 Pro ZS551KL

    Screen diagonal:
    5.5 in
    Aspect ratio (height:width):
    16:9
    Approximate rectangular screen area:
    83.4 cm²
  2. 2. A66

    Screen diagonal:
    4.5 in
    Aspect ratio (height:width):
    16:9
    Approximate rectangular screen area:
    55.8 cm²

Zenfone 4 Pro ZS551KL has approximately 49.4% more rectangular screen area than A66.

Memory variants

Each row compares the same storage capacity. Cells show recorded RAM alternatives, not combined maxima. Not recorded does not mean unavailable in every market.

Recorded RAM for Zenfone 4 Pro ZS551KL, A66, compared at the same storage capacity.
StorageZenfone 4 Pro ZS551KLA66
64 GB 6 GB RAM Unknown
128 GB 6 GB RAM Unknown
A66: Original memory entry

4 GB · 512 MB RAM

Practical features

Explicit Yes and No values are shown directly. Qualified or regional records retain their details. Unknown means the record is missing.

1. Zenfone 4 Pro ZS551KL

NFC:
Yes
Headphone jack:
Yes
Memory card support:
See details microSD · up to 512 GB (uses SIM 2 slot)

2. A66

NFC:
Unknown
Headphone jack:
Yes
Memory card support:
See details microSD · up to 32 GB

Battery capacity

Capacity is not battery life. No endurance test is implied.

Recorded battery capacity

Bars start at zero and share a scale within this chart.

  1. 1. Zenfone 4 Pro ZS551KL

    3600 mAh

    +1600 mAh versus A66

  2. 2. A66

    2000 mAh

Specifications

Open a section for more detail. On narrow screens, swipe sideways or use Left/Right arrow keys while the table is focused. Unknown means missing data, not No. Recorded zero values are shown as recorded.

1. Zenfone 4 Pro ZS551KL2. A66

Everyday essentials
Everyday essentials — specifications for Zenfone 4 Pro ZS551KL, A66.
SpecificationZenfone 4 Pro ZS551KLA66
Dimensions (HxWxD)
  • 156.9 Х 75.6 Х 7.6 mm
  • 136 Х 67.2 Х 11 mm
Weight
  • 175 g
  • 98 g
Technology
  • AMOLED
  • TFT
Screen size
  • 5.5" inch
  • 4.5" inch
Screen resolution
  • 1080 x 1920 px
  • 480 x 854 px
Internal memory Recorded storage / RAM variants. Entries are alternatives, not a combined maximum. Ambiguous formats stay as recorded.
  • 64/128 GB
  • 6 GB RAM
  • 4 GB
  • 512 MB RAM
Memory card support
  • microSD
  • up to 512 GB (uses SIM 2 slot)
  • microSD
  • up to 32 GB
Battery Capacity is not battery life. No endurance test is implied.
  • 3600 mAh
  • Non-removable Li-Ion
  • 2000 mAh
  • Li-Ion
Operating system OS
  • Android 7.1.1 (Nougat)
  • upgradable to Android 8 (Oreo); ZenUI 4
  • Android 4.1.2 (Jelly Bean)
Chipset
  • Qualcomm MSM8998 Snapdragon 835 (10 nm)
Unknown
NFC
  • Yes
Unknown
Headphone jack
  • Yes
  • Yes
Display
Display — specifications for Zenfone 4 Pro ZS551KL, A66.
SpecificationZenfone 4 Pro ZS551KLA66
Touchscreen
  • capacitive touchscreen
  • capacitive touchscreen
Display colors
  • 16M
Unknown
Screen area
  • 83.4 cm2
  • 55.8 cm2
Screen format
  • 16:9 (height:width)
  • 16:9 (height:width)
Screen to body ratio
  • 70.3%
  • 61.1%
PPI /points per inch/
  • 401 PPI
  • 218 PPI
Screen protection
  • Corning Gorilla Glass 5
Unknown
Camera and Video
Camera and Video — specifications for Zenfone 4 Pro ZS551KL, A66.
SpecificationZenfone 4 Pro ZS551KLA66
Rear camera, main
  • 12 MP
  • Dual
  • 3.15 MP
  • Single
Camera specs
  • 12 MP
  • f/1.7
  • 25mm (wide)
  • 1/2.55''
  • 1.4µm
  • 4-axis OIS
  • dual pixel PDAF & laser AF -16 MP
  • 50mm (telephoto)
  • 1/3.1''
  • 1.0µm
  • 2x optical zoom
  • AF
  • 3.15 MP
Functions
  • HDR
  • LED flash
Video
  • 1080p@30fps
  • Yes
Front camera, selfie
  • 8 MP
  • Single
  • 0.3 MP
  • Single
Specifications
  • 8 MP
  • f/1.9
  • 1/3.2''
  • 22mm (wide)
  • 1.4µm
  • PDAF
  • VGA
Performance
Performance — specifications for Zenfone 4 Pro ZS551KL, A66.
SpecificationZenfone 4 Pro ZS551KLA66
Processor CPU
  • Octa-core (4x2.45 GHz Kryo & 4x1.9 GHz Kryo)
  • Dual-core 1.2 GHz
Graphics processor GPU
  • Adreno 540
Unknown
General specs
General specs — specifications for Zenfone 4 Pro ZS551KL, A66.
SpecificationZenfone 4 Pro ZS551KLA66
Release date
  • 2017
  • August
  • 2014
Colors
  • Moonlight White
  • Pure Black
  • White
  • Black
Historical recorded price Legacy catalogue value; date unknown. Not a current offer.
  • 390 EUR
Unknown
Battery life
  • Talking time- Up to 27 h 30 min (3G)
  • Stand by time- Up to 160 h Talking time- Up to 5 h
Body build
  • Front/back glass (Gorilla Glass 5) & aluminum frame
Unknown
Communication and Connectivity
Communication and Connectivity — specifications for Zenfone 4 Pro ZS551KL, A66.
SpecificationZenfone 4 Pro ZS551KLA66
SIM card
  • Hybrid Dual SIM (Nano-SIM
  • dual stand-by)
  • Dual SIM
Network
  • Show all network frequencies: -2G - GSM 850 / 900 / 1800 / 1900 - SIM 1 & SIM 2 -3G - HSDPA 800 / 850 / 900 / 1700(AWS) / 1800 / 1900 / 2100 -4G - LTE band 1(2100)
  • 2(1900)
  • 3(1800)
  • 4(1700/2100)
  • 5(850)
  • 7(2600)
  • 8(900)
  • 17(700)
  • 19(800)
  • 20(800)
  • 28(700)
  • 38(2600)
  • 39(1900)
  • 40(2300)
  • 41(2500) - Global
  • Taiwan LTE band 1(2100)
  • 12(700)
  • 18(800)
  • 26(850)
  • 29(700)
  • 30(2300)
  • 41(2500) - US
  • Canada
  • Brazil LTE band 1(2100)
  • 41(2500) - India
Unknown
Speed
  • HSPA 42.2/5.76 Mbps
  • LTE-A (3CA) Cat12 600/150 or 100 Mbps
Unknown
GPRS
  • Yes
  • Yes
Edge
  • Yes
  • Yes
Wi-Fi
  • Wi-Fi 802.11 a/b/g/n/ac
  • dual-band
  • WiFi Direct
  • hotspot
  • Wi-Fi 802.11 b/g/n
  • hotspot
GPS
  • Yes
  • with A-GPS
  • GLONASS
  • BDS
  • GALILEO
  • Yes
USB
  • Type-C 1.0 reversible connector
  • microUSB
Bluetooth
  • 5.0
  • A2DP
  • EDR
  • LE
  • aptX
  • 2.0
Harmful irradiation Unknown
  • SAR EU - 0.38 W/kg (head) 0.47 W/kg (body)
Music and Audio
Music and Audio — specifications for Zenfone 4 Pro ZS551KL, A66.
SpecificationZenfone 4 Pro ZS551KLA66
Radio
  • FM radio
  • FM radio
Others
  • 24-bit/192kHz audio -DTS sound -Active noise cancellation with dedicated mic
Unknown
Other features
Other features — specifications for Zenfone 4 Pro ZS551KL, A66.
SpecificationZenfone 4 Pro ZS551KLA66
Dop
  • Sensors Fingerprint (front-mounted)
  • accelerometer
  • gyro
  • proximity
  • compass
  • color spectrum
  • Infrared port - Fast battery charging: 50% in 32 min
  • Sensors Accelerometer
  • proximity