The GPO (German Precision Optics) Spectra 4x 4-16x50i G4i Fibre Riflescope (Model RSX441) is a second focal plane optical sight engineered for medium-to-long-range big game hunting and pest control. Built on a single-piece 30 mm aluminium main tube, it combines DoubleHD objective lens technology with fully multi-coated GPObright vacuum coatings to achieve 90% daylight light transmission (ISO 14490-5:2005). The optic features a 50 mm objective lens, an illuminated G4i fiber microdot reticle powered by a CR2032 battery, and a side-focus parallax adjustment capable of dialling from 10 metres to infinity.

Key Features

• Optical Performance: Features a 4x to 16x zoom range paired with a 50 mm objective lens, offering a field of view ranging from 10.4 m down to 2.6 m at 100 m, and 95 mm of eye relief.
• iCONTROL Fiber Reticle: Incorporates a Second Focal Plane (SFP) G4i red microdot with stepless brightness adjustment, an automatic 3-hour shutoff, and an integrated low-battery blinking alert below 15% charge.
• PASSIONtrac Turrets: Provides capped, tool-free zero-resettable windage and elevation adjustments with 1 cm per click at 100 m (0.1 MRAD) and 210 cm of total adjustment travel.
• Lens Protection: Uses PASSIONdrop hydrophobic external coatings to shed water, dust, and debris from outer optical surfaces.
• Durable Construction: Nitrogen-purged, waterproof, and fogproof 30 mm tube rated to handle recoil from standard centre-fire and magnum calibres.

Product Specifications

• Magnification: 4x – 16x
• Objective Lens Diameter: 50 mm (57.2 mm outer diameter)
• Main Tube Diameter: 30 mm
• Reticle: G4i Microdot Illuminated Fiber (SFP)
• Field of View at 100 m: 10.4 m – 2.6 m
• Exit Pupil: 9.5 mm – 3.1 mm
• Eye Relief: 95 mm
• Parallax Adjustment: Side focus, 10 m to infinity
• Turret Value: 1 cm at 100 m (0.1 MRAD) per click
• Total Adjustment Range (Elevation & Windage): 210 cm at 100 m
• Dimensions: 369–370 mm length, 47.9 mm height, 81.2 mm width
• Weight: 629 g
• Power Supply: 1x CR2032 3V Lithium coin cell

Who is the Spectra 4x 4-16x50i G4i Fibre for?

• Open-country deer and pig hunters — Delivers 90% daylight light transmission via a 50 mm objective lens combined with a 4x to 16x magnification range to identify and engage targets during low-light dawn and dusk transitions.
• Spotlighting pest hunters — Provides side parallax adjustment dialling down to a minimum distance of 10 metres, allowing this riflescope to maintain clear focus when illuminating pests at close to medium yardages.

Less suitable for: Close-range shooting under 10 metres where a lower base-power optic (such as a 1-6x or 1-8x LPVO) provides a wider field of view; ultra-long-range precision beyond 800–1,000 metres where a dedicated first-focal-plane optic with 5-25x magnification and exposed tactical turrets is preferable; and ultra-lightweight mountain stalking setups where smaller 1-inch tube scopes under 450–500 g are preferred over this 629 g unit.