The Glock 43X MOS is a semi-automatic pistol chambered in 9mm Luger with a 3.41-inch barrel. It has a Modular Optic System (MOS) slide cut for direct optic mounting and ships with two 15-round magazines. The slide has front serrations, and the frame has a front rail. It is US made. 
 

Key Specifications 

• Brand: Glock 
• Model: 43X MOS 
• Caliber: 9mm Luger 
• Action: Semi Auto 
• Capacity: 15+1 
• Barrel Length: 3.41 inches 
• Color/Finish: Black 
   

Detailed Features 

• Modular Optic System (MOS) slide cut for optic mounting 
• Front serrations on slide 
• Front rail on frame 
• Two 15-round magazines included 
• US made

The 43X MOS has a strong following among concealed carriers who want a slim, optics-ready 9mm. The combination of the MOS cut and the higher-capacity 15-round magazine makes it one of the more capable slim-frame options in this class. Owners who run it with a red dot consistently report good results at typical defensive distances.

The front rail is a meaningful addition for those who run a light, though some find it adds just enough bulk to complicate deep concealment. The front serrations are appreciated for press-checks. Trigger feel is typical Glock, which means familiar for most owners and unremarkable for those coming from aftermarket-trigger pistols.

Value perception is split. Buyers who came from the standard 43X see the MOS variant as worth the premium for the optic-ready capability. A smaller group finds the price high given that the 43X MOS still requires a separately purchased optic, and the two included 15-round magazines help soften that criticism.