Grasshopper;
That was good price you got on that pendulum... most sell it for around $54.00.
I played with the Tru Glo Pendulum as well.
I sighted it in on the ground at 20 yards and then shot it from an elevated position at 35 yards, and found it to be dead on accurate, very easy to setup and switches from fixed pin sight to a pendulum sight with just the turn of a knob.. I was shooting a 1 inch group at 35 yards with it.
If I recall correctly the sight packaging says the pendulum it is on out to 35 yards.
I did find that if you are shooting a slower bow for example in the 240's fps the pendulum will not work out at 35 yards... at 35 yards with the slower bow the arrows were impacting at the knee level of a whitetail when I was aiming at the heart... but they were a tight little group