The description is in error Yes it has a Manual safety and yes MS stands for manual safety specs Specifications and Features: SIG Sauer P320 Nitron Compact Semi Auto Pistol 320C-45-BSS-MS .45 ACP 3.9" Barrel SIGLITE Sights ******* Manual Safety 9 Round Magazine SIG Rail (Picatinny Compatible) Compact Modular Polymer Frame (Matte Black) Stainless Steel Slide (Nitron Finish) Striker Fired Trigger System Sight Radius 5.8" Overall Length 7.2" Overall Width 1.3" Overall Height 5.3" Overall Weight 25.8oz Matte Black Finish

This P320 comes from Sig with a "Manual Safety" MS. ------ •Black grip
•Black Nitron slide
•SIGLITE sights
•Manual Safety
•Includes medium grip module with integral M1913 rail P320® COMMON FEATURES
•DAO Striker-fired trigger with STR (Short Tactile Reset) 6.0# pull
•Modular design lets you interchange trigger groups & grip modules for best fit
•Polymer grip module
•Serialized stainless steel frame assembly
•Stainless steel slide with front/rear cocking serrations
•(2) Trigger Variants (standard & tabbed safety)
•3-Point Takedown Safety System - No trigger pull or tools required
•Striker safety
•Disconnect safety
•No external safety or decocking lever
•Includes (2) steel mags
•Width: 1.4"

The description is in error Yes it has a Manual safety and yes MS stands for manual safety specs Specifications and Features:
SIG Sauer P320 Nitron Compact Semi Auto Pistol 320C-45-BSS-MS
.45 ACP
3.9" Barrel
SIGLITE Sights
******* Manual Safety
9 Round Magazine
SIG Rail (Picatinny Compatible)
Compact Modular Polymer Frame (Matte Black)
Stainless Steel Slide (Nitron Finish)
Striker Fired Trigger System
Sight Radius 5.8"
Overall Length 7.2"
Overall Width 1.3"
Overall Height 5.3"
Overall Weight 25.8oz
Matte Black Finish