Phone Comparison - Karbonn KT21 Express vs Asus Zenfone 2 ZE551ML vs Asus Zenfone Zoom ZX550

general General Info

Manufacturer Karbonn Asus Asus
Announced 2012 January 2015 January 2015
Status Available Available - March 2015 Coming Soon - Q2 2015
Price - Rs. 14,999 ($220.57) [Similarly Priced] Rs. 37,999 ($558.81) [Similarly Priced]
Colors Black Osmium Black, Sheer Gold, Glacier Gray, Glamor Red, Ceramic Whit Meteorite black, Glacier white
Form Factor Candybar Candybar Candybar
Dimension - 152.5 x 77.2 x 10.9 mm
(6 x 3.04 x 0.43 in)
158.9 x 78.8 x 12 mm
(6.26 x 3.1 x 0.47 in)
Weight - 170 g (6 oz) 185 g (6.53 oz)
2G Network GSM - SIM 1 & SIM 2 GSM 850 / 900 / 1800 / 1900 - SIM 1 & SIM 2 GSM 850 / 900 / 1800 / 1900 - SIM 1 & SIM 2
3G Network N/A HSDPA 850 / 900 / 1900 / 2100 HSDPA 850 / 900 / 1900 / 2100
4G Network - LTE 700 / 800 / 850 / 900 / 1700 / 1800 / 1900 / 2100 / 2600
(Bands 1, 2, 3, 4, 5, 7, 8, 9, 17, 18, 19, 20, 28, 29)
LTE 700/800/850/900/1700/1800/1900/2100/2600
(Bands 1, 2, 3, 4, 5, 7, 8, 9, 17, 18, 19, 20, 28, 29)
Messaging SMS, MMS SMS, MMS, Push Mail, EMail, IM SMS, MMS, Push Mail, EMail, IM

hardware Hardware and OS

OS - Android OS, v5.0 (Lollipop) Android OS, v5.0 (Lollipop)
Processor - Quad-core 2.3 GHz
Quad-core 1.8 GHz, Intel Atom Z3580
Intel Atom Z3560
Quad-core 2.3 GHz, Intel Atom Z3580
GPU - PowerVR G6430 PowerVR G6430
RAM N/A 2/4 GB 4 GB
Internal Memory - 16/32/64 GB 32/64/128 GB
External Memory microSD, up to 32 GB microSD, up to 64 GB microSD, up to 64 GB

display Display

Type TFT capacitive touchscreen IPS Capacitive Touchscreen, Corning Gorilla Glass 3 IPS Capacitive Touchscreen, Corning Gorilla Glass 3
Colors TFT capacitive touchscreen 16M colors 16M colors
Size 2.8 inches 5.5 inches 5.5 inches
Resolution 240 x 320 pixels (143 ppi) 1080 x 1920 pixels (401 ppi) 1080 x 1920 pixels (403 ppi)
Screen-to-Body Ratio - 70.67% 65.79%
Multi-Touch yes yes yes

multimedia Multimedia

3.5mm Jack yes yes yes
Radio FM radio, FM recording Yes No
Games Yes + Downloadable Yes + Downloadable Yes + Downloadable
Loud Speaker yes yes yes

camera Camera

Rear Camera 3.15 MP, 2048x1536 pixels 13 MP, 4128 x 3096 pixels 13 MP, 4128 x 3096 pixels
Flash LED flash dual-LED (dual tone) Dual-tone Flash
Features - Auto focus, Geo-tagging, Touch Focus, Face Detection, Panorama, HDR Optical Image Stabilization,Geo-tagging, Touch Focus, Face Detection, Panorama, HDR
Video Yes 1080p@30fps 1080p@30fps
Front Camera No [Similar] 5 MP [Similar] 5 MP [Similar]

connectivity Connectivity and Data Rate

GPRS Yes Yes Yes
Edge Yes Yes Yes
3G N/A HSPA 42.2/5.76 Mbps, LTE Cat4 150/50 Mbps HSPA 42.2/5.76 Mbps, LTE Cat4 150/50 Mbps
Bluetooth Yes v4.0, A2DP, EDR v4.0, A2DP, EDR
Wi-Fi No Wi-Fi 802.11 a/b/g/n/ac, Wi-Fi Direct, hotspot Wi-Fi 802.11 a/b/g/n/ac, Wi-Fi Direct, hotspot
USB Yes microUSB v2.0, USB Host microUSB v2.0, USB Host
GPS No Yes, with A-GPS, GLONASS Yes, with A-GPS, GLONASS
Browser Yes HTML5 HTML5

memory User Memory

Phonebook 2000 entries Practically unlimited entries and fields, Photocall Practically unlimited entries and fields, Photocall
Call Records Yes Practically unlimited Practically unlimited
Internal - 16/32/64 GB, 2/4 GB RAM 32/64/128 GB, 4 GB RAM
Expandable Storage microSD, up to 32 GB microSD, up to 64 GB microSD, up to 64 GB
USB OTG - Supported Supported

Apps Sensors

Fingerprint fingerprint not supported fingerprint not supported fingerprint not supported
Proximity Sensor proximity sensor present proximity sensor present proximity sensor present
Accelerometer Sensor accelerometer sensor not present accelerometer sensor present accelerometer sensor present
NFC NFC not supported NFC supported NFC supported

battery Battery

Type Li-Ion Battery Non-removable Li-Po Battery Non-removable Li-Po Battery
Capacity 1000 mAh 3000 mAh 3000 mAh
Stand by - - -
Talk Time - - -