The Specialist Equipment is your R1 (Where your standard grenades use to be)
This Trophy Requires you to get 10 Medals based on the Special Issue Equipment
Some examples are as follows: (Confirmed)
• Pure Gold - Kill 2 or More Enemies rapidly while gold ammo is active (Crash)
• Lights Out - Kill 2 or more enemies rapidly while they are stunned by your 9-bang (Ajax)
• Ambushed - Kill 2 or more enemies with a Mesh Mine (Nomad)
• Mayhem - Kill 2 or more enemies rapidly with a Cluster Semtex (Battery)
• Lit and Hit - Kill 2 or more enemies rapidly while they were within range of your Sensor Dart (Recon)
I noticed the theme of the medals is "Kill 2 or more enemies rapidly" so below are possibly the other Specialist Equipment Based Medals, If anyone can confirm that would be great
Possible Medals (un-confirmed)
• Kill 2 or more enemies rapidly with the Reactor Core (FireBreak)
• Kill 2 or more enemies rapidly after deploying the Seeker (Prophet)
• Kill 2 or more enemies rapidly with the Razor Wire (Torque)
• Kill 2 or more enemies rapidly after deploying the Tac-Deploy (Seraph)
• Kill 2 or more enemies rapidly after using the Grapple Gun (Ruin)
Just get 10 of any of these medals (They Don't have to be the same medal) and *Ding* There is your trophy :D
Trophy Should Unlock not long after gaining the 10th medal or at the end of the game!
You Can See how many medals you have by pressing options in the multiplayer menu and going to Barracks then selecting Medals then moving over to the Specialists Section