The “Angle Cosine Indicator,” is a simple tool for hunters in mountainous terrain, and utilized to obtain their corrected for gravity distance to target.
The ACI is a vault solid, water resistant precision instrument; quiet and made from aircraft grade aluminum, which is anodized in a flat black color.
The Co-Sine numbers are Laser Engraved onto the body in five (5) degree increments.
The lens is shatter proof, shock proof and resistant to chemicals such as acetone and cleaning solvents.
Completely mechanical, there are no batteries to fail, no electronics to fail.

There are several ways to mount the device. One way is to utilize a short, Weaver Base scope ring, which is mounted onto the scope tube, at 90 degrees.
How does it work? Simple...
1. Determine full line-of-sight distance to target.
2. Determine the ′angle cosine′ by aiming at the target, then looking at the indicator on the ACI.
3. Multiply the full line-of-sight distance to target by the angle cosine number to determine the corrected for gravity distance.
4. Adjust the sight elevation knob (come-ups) on your scope, for the ′corrected range′.

There are several ways to mount the device. One way is to utilize a short, Weaver Base scope ring, which is mounted onto the scope tube, at 90 degrees.

How does it work? Simple...

1. Determine full line-of-sight distance to target.

2. Determine the 'angle cosine' by aiming at the target, then looking at the indicator on the ACI.

3. Multiply the full line-of-sight distance to target by the angle cosine number to determine the corrected for gravity distance.

4. Adjust the sight elevation knob (come-ups) on your scope, for the 'corrected range'.