ASLI (Angle Slope Level Indicator)

Our USA-made ASLI device gives the long distance shooter a single, durable, light weight, precision engineered, and hermetically sealed unit. One gauge will provide both cant and angle of fire. The ASLI can be mounted on either side of the scope accommodating for right and left handed shooters as well as upside down depending on scope height. The easy to read angle indicator provides both degrees of angle and corresponding cosine.

For long range shots, the clear and bright ASLI is invaluable for keeping your rifle horizontal and true. Any minor deviation from being level will cause greater misses at greater distances. The device attaches directly to your scope via 34mm ring and also comes with a 30mm inserts to accommodate a smaller tube size. The unit may be painted to match your scope and doesn't require batteries.

The ASLI comes with a protective rubber cap, 34mm ring and 30mm inserts, Loctite, 7/64th hex key and instruction card.

The ASLI may be used along with ATragMX and our CATS targets. Simply enter the cosine value into the ATrag software to obtain your proper hold. Practice with our CATS targets to achieve perfect alignment between your scope and rifle.

To obtain the true horizontal distance to target when utilizing the ASLI:

Multiply the exact range to target by the cosine value given, hold wind for the original distance given and use your new elevation hold to hit any target at any range.

Distance to target: 475

cosine Value: .91

475 yards x .91= 432 yards

True horizontal distance: 432 yards

$145  ASLI
To purchase, call (650) 588-8862

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Features Specs Brochures Manuals Demos


  • Made in USA
  • Magnified lens for easy to read cosine values, for a fast acquisition of angle shots
  • Frosted outer housing for decreased light reflection in and off the unit
  • Magnetically dampened to quickly halt oscillation for fast readings
  • Clear, large numbers for better visibility in low light
  • Readings in both vertical angle degrees and corresponding cosine value
  • Versatile mounting for left, right, bubble up or upside down
  • Easy-to-paint plastic housing, to blend ASLI into your scope and gun
  • Tested to withstand the repeated G-shock pounding of a 50cal BMG
  • Must have for any high or low angle shooting
  • 34mm mounting ring and 30mm adaptor inserts included.



  • Height: 1.85"
  • Width:: 1.5"
  • Depth:: 1.15"
  • Weight: 1 oz, 1.5oz with cover
  • Housing: Backside - hardened Ballistic Polymer; Clear Cover - high-impact poly carbonate, frosted for reduced glare in bright conditions
  • Angle Indicator Wheel:

    • Precision machined aluminum to a tolerance of +/- .004"
    • All markings of calibration are 360 degrees laser engraved
    • Calibration markings:

      • – Designed to be read and used from any of the 4 mounting positions
      • – To facilitate different shooters and methods that they employ to calculate hold, the ASLI incorporates 2 scales of measuring angles:

        • Outer Ring: calibrated in Cosign
        • Inner Ring: calibrated in Degrees
    • The Indicator Wheel is self adjusting to 0 degrees.

  • Rare Earth Magnets: Rare Earth Magnets damp Indicator Wheel isolation
  • Leveling Bubble: Precision bubble level enclosed in a precisely machined portion of the clear hi-impact Polycarbonate cover
  • Precision Machined: All secondary (2nd) parts are precision machined to insure proper fit and functionality
  • Nitrogen Purged: The ASLI is Dry Nitrogen Purged and hermetically sealed
  • Dust: The ASLI is dust proof
  • Water: The ASLI is water proof to 20 meters in depth
  • Shock: The ASLI is shock proof (Note: the ASLI is a ruggedized unit specifically designed to be used with heavy recoiling rifles under adverse conditions. The ASLI is not designed to withstand deliberate abuse or severe mishandling.)
  • Mechanical: The ASLI unit uses no batteries and has no illumination signature
  • Protective Rubber Cap: The ASLI unit comes equipped with a rubber cover to protect it in the field when not in use



Accessories Brochure
Aiming Accessories brochure in PDF format, 822 kb download. Click here to view now.

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ASLI Manual
How ASLI works. User's manual in PDF format, 807 kb. Click here to view now.

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ASLI Product Demo
Measure cant and slope while looking through your scope. Click here to view now.

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