Features:
Very user-friendly, easy to learn, and easy to install.
The processor is an ELM327.
The output protocol (connection to laptop) is USB.
The software supports two platforms - DOS and Windows.(not including Win 7)
Read diagnostic trouble codes, both generic and manufacturer-specific, and display their meaning (over 3000 generic code definitions in the database).
Clear trouble codes and turn off the MIL ( Check Engine light).
Display current sensor data, including:
Engine RPM
Calculated Load Value
Coolant Temperature
Fuel System Status
Vehicle Speed
Short Term Fuel Trim
Long Term Fuel Trim
Intake Manifold Pressure
Timing Advance
Intake Air Temperature
Air Flow Rate
Absolute Throttle Position
Oxygen sensor voltages/associated short term fuel trims
Fuel System status
Fuel Pressure
Many others...

Specifications:
OBDII Protocols:
ISO15765-4 (CAN)
ISO14230-4 (KWP2000)
ISO9141-2
J1850 VPW
J1850 PWM
Output protocol: RS232
Baud rate: 9600 or 38400
Indicator LEDs: OBD Tx/Rx, RS232 Tx/Rx, Power
Operating voltage: 12V, internal protection from short circuits/overvoltages
Nominal idle current: 45mA
Color: Back + Orange + Blue
Item Size: 8.8 * 4.6 * 2.5cm
Package Size: 20 * 15 * 2.5cm
Item Weight: 130g
Package Weight: 139g
USB Cable Length: 176.5cm

Free software:
Scantool.net
GM Mode 22 Scan Tool by Terry
OBD Gauge for PalmOS and Pocket PC by Dana Peters
OBD Logger by Jonathan Senkerik
OBD-II ScanMaster by Wladimir Gurskij (ScanMaster 3.52 - local copy)
obd2crazy.com
OBD2 Scantool by Ivan Andrewjeski
OBDII for ELM322 by David Huffman
pyOBD by Donour Sizemore for MacOSX and Linux
RDDTC by Pete Calinski
Real Scan by Brent Harris
ScanTest for Pocket PC by Ivan Ganev aka a-ser
wOBD by WDT

Aavailable cars:
Benz 2001/02/03 W203 C200K (ISO)
BMW X5 2002 (ISO) -3, -5, X5, Z3, Z4, Z8, 740I, 740L, 750IL, (ISO1941)
Chevrolet Aveo (ISO)
Citroen C3 2004 (ISO)
Daihatsu YRV 2005 (ISO)
Daihatsu YRV Turbo 2006 (ISO)
Fiat Tipo 2002 (ISO)
Ford New ocus 2006(CAN)
Honda Accord 2006 JDM (ISO)
Honda Accord Euro R 2004 JDM (ISO)
Honda City GD8 (ISO)
Honda Civic ES 1.6A (ISO)
Honda Integra Type R DC5 JDM (ISO)
Honda Jazz 1.4M (ISO)
Hyundai Accent 2004 (ISO)
Hyundai Getz 1.3A 2004 (ISO)
Hyundai Getz 1.6M 2004 (ISO)
Hyundai Matrix 2004 (ISO)
Hyundai Santa Fe 2.4A (ISO)
Hyundai Sonata GLS (ISO)
Hyundai Sonata 2005 (ISO)
Hyundai Tuscani FX (ISO)
Kia Carens 2005 (ISO)
Kia Magentis 2005 (ISO)
Kia Rio LS (ISO)
Kia Sorento SUV 2005 (ISO)
Lexus es300 Mazda 2 (CAN)
Mazda 5 (CAN)
Mazda 6 (CAN)
Mazda Premacy 2001 (ISO)
Mazda RX8 (CAN)
Mitsubishi Colt 2003 (ISO)
Mitsubishi Colt Plus 2005 (ISO)
Mitsubishi Eclipse(GST--Turbo Car can be tested for the year 1995-2000; RS/GS----1994-1996 GS all can do; Turbo Car for the year 1996-2000, only have speed and TPS, can clear the DTCS)
Mitsubishi Lancer Evolution IX 2006 (ISO)
Mitsubishi Pajero 3.5 V6 2006 (ISO)
Nissan Sunny B14 (ISO)
Nissan Sunny VIP FB15 (ISO)
Nissan X-Trail 2.0L 2004 (ISO)
Nissan X-Trail 2.5L 2004 (ISO)
Peugeot 206 2001 –Only can show RPM
Peugeot 206 (ISO)
Peugeot 307 (ISO)
Peugeot 407 (ISO)
Renault Megane II 2005 (ISO)
Renault Kangoo 2006 (ISO)
Subaru Impreza 1.6TS 2002 (ISO)
Subaru Impreza WRX 2005 (ISO)
Toyota Camry 2.0A 2004 (ISO)
Toyota Camry 2.4A 2005 (ISO)
Toyota Corolla Altis 1.6A 2005 (ISO)
Toyota Corolla GLXi G8 1999 (ISO)
Toyota Corolla G9 2002 (ISO)
Toyota Vios 2004 (ISO)
Nissan Sunny (N16)
Nissan Cefiro (Teana) 2005
Nissan sentra 1.8 2000/2005
Nissan Cefiro (Teana) 2005
Proton Perdana V6
Subaru Legacy GT 2005
Toyota camry 2002
Toyota Wish JDM (Missing Pin 5 in DLC)
Toyota IST JDM (Missing Pin 5 in DLC)
Toyota altis 1.8 2004
Peugeot 206 2000
Suzuki Jimny 1.3 2000
Diesel engine

Package including:
1 * ELM327 USB interface
1 * CD software