Key Features:

• Aluminum design
• Mac OS X 10.14 pre-installed- unit can be downgraded to El Capitan / Sierra or older OS X for free!!
• Intel Core i5-2400S 2.5 GHz quad-core processor
• 3.3 GHz Max Turbo Frequency 
• 6 MB Intel Smart Cache, 5 GT/s DMI
• 8 GB DDR3 RAM
• 1TB  HDD
• Slot-loading 8x DVD±RW DL SuperDrive
• AMD Radeon HD 6750M with 512 MB of GDDR5 memory
• Built-in stereo speakers with 17-watt digital amplifier
• Built-in microphone
• Built-in 10/100/1000BASE-T Gigabit Ethernet
• Built-in AirPort Extreme (802.11n)
• Built-in Bluetooth 2.1+EDR (Enhanced Data Rate) module
• Built-in FaceTime HD camera
• SDXC card slot
• Built-in 21.5-inch glossy LED-Backlit widescreen TFT active matrix LCD display (1920 x 1080) with IPS technology

I/O Ports:

• Four (4) USB 2.0 ports
• One (1) FireWire 800 port
• One (1) Thunderbolt port
• One (1) RJ-45 Ethernet port
• Optical digital audio output/headphone out
• Optical digital audio input/audio line in