Description USED comes with everything you see in photos including Holosun optic! 
FDE B5 grip changed out is the only modification!!
The MPX line from Sig Sauer is versatile enough to adapt to any environment you may find yourself in. It features an unconventional design to match its unrivaled performance. Rigorously developed and tested, the MPX was built to withstand any challenge thrown its way. The Sig Sauer MPX redefines the submachine category with its high level of modularity and reliability in the worst conditions. There's nothing else out there like the MPX, just how Sig Sauer likes it. Sig Sauer is trusted by many military forces, law enforcement agencies, and commercial users worldwide for their reliable, renowned firearms.
MPX rifles/pistols incorporate the following features:
Short-Stroke Piston System - Reduce recoil and fouling with the gas-operated, short-stroke piston system. The bolt is held open on the last round fired.
Rotating Bolt System - A fully locked and closed rotating bolt system provides maximum safety in case of bullet or water obstruction in the bore.
AR-Style, Ambidextrous Control - No retraining required. The SIG MPX features a familiar, AR-style ambidextrous selector and magazine release.
Monolithic Upper Reciever - The monolithic upper receiver features an integral M1913 rail at 12 o’clock and a free-float barrel system.
SIGTAC SBX Stabilizing Brace (MPX Pistols) - Improves the single-handed shooting performance. MPX Carbines feature a folding, collapsible stock.
Rear Charging Handle - Does not interfere with rail-mounted accessories.
Stock Options - Maximize performance while conserving space with telescoping or folding stocks.
Specifications
SKU: PMPX-3B-CH-Sig
UPC: 798681599011
MPN: PMPX-3B-CH 
Action: Gas Piston - Semi-Automatic
Barrel Length: 3.5" - 1:10 Twist
Barrel Thread Pitch: Integrated Flash Hider - Pistol Compatible with other MPX Barrels
Caliber: 9mm
Frame Finish: CERAKOTE E190
Grips: Rattler Grip
Magazine Capacity: 30 Round Magazines (2)
Magazines Included: (1) 20 Round
Rifle Barrel Length: 3.5"
Rifle Stock: Pistol Brace
Safety: AR Selector Switch
Scope Mount: Picatinny Rail
Weight: 4.5 lbs.
Caliber or Gauge: 9mm
Handedness: Right Hand