Strike Industries Polymer Backup Sights - SI-SPBUS

Strike Industries Polymer Backup Sights

Backups for your backups—compact, tool-less, and mission-ready.

The Strike Industries SPBUS (Polymer Backup Sights) delivers versatile, low-profile sighting with an innovative twist—built-in backup sights even when stowed. Whether you need an offset CQB solution or an inline backup to a red dot, SPBUS offers dual-function performance in a lightweight, tool-less, adjustable design.

Constructed from Strike’s SI Polymer Extreme with steel inserts for durability, these sights mount easily to any Picatinny rail. The front sight features elevation adjustment, and the rear sight offers windage adjustment and dual apertures (large: 4.70mm / small: 1.75mm). Flip them up for standard use or utilize the integrated stowed-sight system for emergency targeting.

Note: Slightly taller than standard A2 sights. Optimized for use as a front/rear pair—do not mix with other brands/models.

Features

• Dual-mode use: Traditional flip-up or stowed backup aiming
• Tool-less adjustment for windage and elevation
• Offset-compatible low-profile design to reduce snagging
• Steel-reinforced mounting tabs for secure attachment
• Rear sight with quick-toggle dual apertures (CQB or precision)
• The front post can be painted for visibility customization
• Fits any MIL-STD 1913 Picatinny rail
• Includes mounting screws, hex tool, and threadlocker

Specifications

• Material: SI Polymer Extreme w/ steel inserts
• Color: Black
• Weight: Front – 0.60 oz | Rear – 0.70 oz
• Height (Deployed): Front – 1.77″, Rear – 1.76″
• Height (Stowed): Front – 0.54″, Rear – 0.56″
• Length (Deployed): 1.90″ (both)
• Adjustment:
  • Windage: 1 MOA clicks (± at 14.5″/20″ sight radius)
  • Elevation: 1.24″–1.71″ per 100m, depending on sight radius
• Apertures: 4.70mm & 1.75mm (rear)
• Mount Type: Picatinny
• Compatibility: Optimized for AR-15/M4 platforms