https://support.apple.com/en-us/112568

Specs

• CPU: 2.6GHz quad-core Intel Core i7 processor (Turbo Boost up to 3.6GHz) with 6MB L3 cache
• RAM: 16GB of 1600MHz DDR3 SODIMM memory
• Storage: NONE INCLUDED, fits any SATA 2.5" HDD or SSD
• GPU: Dedicated Nvidia GeForce GT 650M with 1GB of GDDR5 memory and automatic graphics switching
• Display: 15.4-inch (diagonal) LED-backlit glossy display, 1440x900 native resolution
• Ports and Expansions:
  • MagSafe power port
  • Gigabit Ethernet port
  • FireWire 800 port (up to 800 Mbps)
  • Two USB 3 ports (up to 5 Gbps)
  • Thunderbolt port (up to 10 Gbps)
  • Audio line in
  • Audio line out
  • SDXC card slot
  • Kensington lock slot
  • 8x SuperDrive
• Wireless:
  • 802.11n Wi-Fi wireless networking;3 IEEE 802.11a/b/g compatible
  • Bluetooth 4.0 wireless technology
• Camera: 720p FaceTime HD camera
• Dimensions:
  • Height: 0.95 inch (2.41 cm)
  • Width: 14.35 inches (36.4 cm)
  • Depth: 9.82 inches (24.9 cm)
  • Weight: 5.6 pounds (2.56 kg)

What is Included

• 15" Mid 2012 MacBook Pro
• 85W MagSafe Charger
• iFixIt Screwdriver with all driver heads needed to open and service this laptop
• Mounting hardware for the 2.5" SATA drive (not included)

Servicing Information

• All iFixIt guides
• Replacing the storage
• Reinstalling MacOS
• Reset SMC (Power and battery management) [^1]

[^1] Battery was replaced with iFixIt's replacement battery about five years ago and should still be in good condition.