The Canadian company Elcan made a couple of odd scopes in the C79/M145 family of optics. These are fixed 3.4X scopes with external adjustments.
The C79 scope are mainly for rifles, and are tritium powered like ACOGs. Usually when you see a used C79 for sale, the tritium is old and dim enough that it is unusable. C79 scopes are mainly seen in use by the Canadian military.
The M145 MGO (pictured above) was adopted by the US for use on the M249 and the M240 machine guns. While I was in the Corps, they were generally thought poorly of by the Machinegunners I knew. This was partly due to the lack of training and trigger time with them, and mostly due to where we were observing was often closer ranges.
These Elcans are larger and about a half pound heavier then the more available 4x ACOGs. The external mounts are also prone to damage and debris.
The M145 pictured above has the machinegun reticle:
The gaps in the reticle represent 40inch wide and 60 inches tall at the respective range.
Scope adjustments are very coarse. .25 mil, or about .84 MOA per click. Windage is easily adjusted with a coin or similar tool. There is a lock to prevent unwanted elevation adjustment, but on this particular M145 that lock is broken. Elevation adjustment is made by lifting the latch above the rear dial wheel and turning the wheel.
Battery life is said to be about 7 days at max brightness. I haven’t tested that yet. Eye relief is said to be an inch longer than the ACOG. Personally I found it to be very unforgiving.
Most reviews of the C79 and the M145 are very negative and there is good reason for it. They simply are not worth the cost when there are other options like the Trijicon ACOG.