1x20 Ultra-Compact Prism Scope

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This Monstrum Tactical Rifle Scope is backed by a 1 Year Warranty

  • Includes: 1x20 Prism Scope, CR2032A Battery, Lens Cloth, Lens Cover
  • Materials: 6061 Aircraft Grade Aluminum
  • Compatibility: Rifles with Picatinny Rails.
  • Scope Range: Close Range, 100+ Yards.
  • Magnification: 1x
  • Objective Diameter: 20 mm
  • Eye Relief: 3.0-3.5 in
  • Weight: 10 oz
  • Length: 4.3 in
  • Color: Black
  • Fog & Water Resistant? Yes (Nitrogen Sealed)
  • Warranty: 1 Year Warranty

The Monstrum Tactical S120P is an ultra compact prism scope with 1x magnification and a 20mm objective lens, ideal for close quarter tactical situations and rapid short range target acquisition out to 100+ yards. This scope uses a glass prism optical system rather than a refracting lens system like traditional scopes, allowing for better optical quality in a much smaller package. The crystal clear optics give a comfortable eye relief of 3.0-3.5 inches. The reticle can illuminate in red with 11 levels of intensity or viewed in black when off to cover most lighting environments.

Download the S120P-B Manual

1 Review Hide Reviews Show Reviews

  • 1x20 Prism Scope - great value

    Posted by Matt on May 20th 2019

    As a preliminary matter, Monstrum’s customer support is outstanding. I was looking for a 2x prismatic scope with the crosshair and segmented circle. Shane provided this at my request.

    Once the ocular is properly adjusted, this scope provides a crisp, bright view and a very crisp reticle image. The view stays in focus down to extraordinarily short ranges. The eye relief is substantially greater than 3 ½ inches. I would guess that the eye relief is five or 6 inches, but still usable down to 3 inches. The eye box is forgiving.

    Now that Leupold no longer sells its prismatic, the only other choices in this niche are Vortex and Primary Arms products at several hundred dollars with shorter eye relief and circle dot reticles.

    My only problem with this scope is not the scope itself, but the pedestal on which it sits. It is difficult to get this tightly attached to a picket any receiver so that the amount is solid. Fortunately, the 1x20 uses a 30 mm tube. After mounting this in a single piece AR scope mount, 1 inch groups at 50 yards were the norm.

    The only improvement I could make to this scope would be to give it the same sort of mounting system with two thumb nuts and a longer rail engagement.

    It’s a great value.


All orders are shipped from our Warehouse in Orange County, CA via the United States Postal Service. Depending on your distance from California, your package delivery date can vary. Standard Shipping will arrive in 3-10 business days. Expedited shipping will arrive in 1-3 business days. Our shipping rates are:

  • For orders between 0–$49.99: Standard - $4.99 | Expedited - $8.99
  • For orders between $50–$149.99: Standard - FREE | Expedited - $8.99
  • For orders $149.99 and up: Standard - FREE | Expedited - $14.99

Next Day Air Shipping is not available. We are not responsible for delays caused by USPS & UPS or for abnormal weather. Shipping fees are non-refundable. Orders placed before 10am PST, Monday-Friday will be shipped same day. Orders placed after 10am or on the weekends/holidays will be shipped on the next general workday. Upon shipment, you will receive an email confirmation with tracking information. If there is an issue with a missing package, please contact your local post office to open an investigation and then contact our customer support staff for help.

Returns Policy

The Monstrum Tactical 30 Day Satisfaction Guarantee:
Monstrum Tactical stands behind each of our products with a 30-day no questions asked return policy. Return items must be returned in unused condition with all original parts and packaging. The customer is responsible for shipping. Contact our customer service department to begin the process.

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