Sig Sauer P320 Pro 9mm XRY3 ROMX 3.6" Barrel Black (Model 8901566)

The Sig Sauer P320 Pro 9mm is a factory-built optics-ready slide assembly that lets you run a modern reflex sight without sacrificing the option to use your standard-height iron sights. Built on the X-SERIES platform, this 3.6" barrel slide ships pre-mounted with a ROMEO-X PRO sight and includes X-RAY3 day/night iron sights, giving you a complete, redundant aiming system right out of the box. The low-mounted optic profile means your backup sights remain usable without suppressor-height modifications—a practical setup for shooters who want flexibility on the range or in the field.

This is a slide assembly designed for the Compact frame size and works with both X-SERIES and non-X-SERIES grip modules, making it a straightforward retrofit for existing P320 owners or a core component for a fresh build. The black Nitron finish is durable and low-maintenance, and the assembly is chambered in 9mm Luger. Important note: this slide is compatible only with 9mm, .357 SIG, and .40 S&W fire control units—it will not function with a .45 ACP FCU, so verify your lower before ordering.

Whether you're setting up a duty-style carry gun, a competition platform, or just want a modern optics solution without the complexity of suppressor-height sights, the P320 Pro delivers a no-compromise middle ground. The ROMEO-X PRO is Sig's proven reflex sight, and pairing it with X-RAY3 sights gives you a system that works in daylight, low light, and if your optic fails.

Key Features

• Factory-installed ROMEO-X PRO reflex sight with low slide profile—compatible with standard-height iron sights
• Comes complete with X-RAY3 day/night backup sights
• Fits P320 Compact grip modules (X-SERIES and non-X-SERIES)
• Black Nitron finish for corrosion resistance and durability
• Optics-ready design on PRO (DeltaPoint Pro) footprint
• Chambered in 9mm Luger

Specifications

Frequently Asked Questions

Will this slide work with my P320 Compact frame?

Yes. This slide assembly is designed for the P320 Compact size and is compatible with both X-SERIES and non-X-SERIES Compact grip modules.

What fire control units is this compatible with?

This slide is compatible with 9mm, .357 SIG, and .40 S&W fire control units only. It will not function with a .45 ACP FCU.

Do I need suppressor-height sights with the ROMEO-X PRO?

No. The ROMEO-X PRO is mounted low enough that your standard-height X-RAY3 iron sights remain fully usable as backups, so you don't need suppressor-height sights.

What's included in the box?

This is a slide assembly. It comes factory-mounted with the ROMEO-X PRO optic and X-RAY3 sights. A barrel is not included; you'll need to source a 9mm barrel separately for your caliber.