Mini DisplayPort to VGA, DVI or HDMI converter offers a three-in-one solution for connecting an mini DP source such as a Thunderbolt™-enabled MacBook Pro® / MacBook Air® to a VGA, DVI, or HDMI Display. Ensuring compatibility with almost any display, television or projector, this compact and lightweight adapter offers the ideal plug-and-play solution for travel, or BYOD (Bring Your Own Device) applications around the office.

This product with three output ports, and you can choose one of them to use at a time as you demand, the functions of the port as followings:
DVI output, connect the DVI devices using a DVI cable.
HDMI output, connect the HDMI devices using a HDMI cable.
VGA output, connect the VGA devices using a VGA cable.
Mini Display Port, connect Mac Book, Mac Book Pro, or Mac Book Air.
Note:
please make sure that your Mac has mini DP port or Thunderbolt port
Only one of the 3 outputs could be used at a time, you cannot use all of them simultaneously
The following Mac/Apple computers support audio pass-through via Mini DisplayPort.

MacBook 13" Model 7,1 (Mid 2010)
MacBook Pro 13" Model 7,1 (Mid 2010)
MacBook Pro 15" Model 6,2 (Mid 2010)
MacBook Pro 17" Model 6,1 (Mid 2010)
MacBook Pro 13" Model 8,1 (Early 2011 / Thunderbolt)
MacBook Pro 15" Model 8,2 (Early 2011 / Thunderbolt)
MacBook Pro 17" Model 8,3 (Early 2011 / Thunderbolt)
MacBook Air 11" Model 3,1 (Late 2010)
MacBook Air 13" Model 3,2 (Late 2010)
Mac mini Model 4,1 (Mid 2010)
iMac 27" Model 10,1 (Late 2009)
iMac 27" Model 11,1 (Late 2009)
iMac 21.5" Model 11,2 (Mid 2010)
iMac 27" Model 11,3 (Mid 2010)
Mac Pro Model 5,1 (Mid 2010)
Microsoft Surface Pro & Pro 2 3

Features:

Support HDMI/DVI/VGA output with the max resolution of 1920x1080p@60Hz.
Support Mini Display Port 1.1a Dual-mode input.

The HDMI can support audio output for iMac (Late 2009) and Mac Book Pro (Mid 2010)
225MHz/2.25Gbps per channel (6.75Gbps all channel), 12bit per channel (36bit all channel) deep colour.
Automatic detect the display by plugging and unplugging it.
Powered from Mini Display Port source.

You can connect the display to one of HDMI/DVI/VGA output ports.

Input Signal: Mini Display Port 1.1a
Output Video: HDMI/DVI/VGA
Input: Mini Display Port Male 20pin
Output: HDMI Female Type A 19pin
Connector: DVI Female (24+1) VGA Female 15Pin
Vertical Frequency Range:50/60Hz
Video Amplifier Bandwidth:2.25Gbps/225MHz
HDMI/DVI/VGA:480i/480p,576p,720p,1080i/1080p
External Power Supply: No external power needed
Power consumption (Max):700mW
The Length of the cable(end to end): 20cm
Colour: snowy white
Package weight:1.9 oz./54g

How to use it:

The product is easily and conveniently use, with three output ports: DVI VGA HDMI and a Mini Display Port and you can use one of them at a time as your demand, when you want to use the DVI output, you just need to connect the DVI devices using a DVI cable. And when you want to use the HDMI output, you just need to connect the HDMI devices using a HDMI cable. When you want to use the VGA output, you just need you connect the VGA devices using a VGA cable. The Mini Display Port need to connect Mac Book, Mac Book Pro, or Mac Book Air.

How to set the resolution :
You can go into “System Preferences” > “Display“. You’ll be able to see 2 display preferences dialog, one for your prime MacBook display and one for the external monitor. You can use the settings in dialogs to adjust the screen resolution, colour intensity and if you have a monitor that can be swivelled (rotated) you can tell Mac OSX to rotate the display to a certain angle for that particular display.

Mac Book Air, Mac Book Pro, iMac, and Mac mini with thunderbolt ports since 2011 are all supported.

Mac Book Air, Mac Book Pro, iMac, and Mac mini or PC with mini display port are also supported.