I am a former pendulum owner. I owned the keller pendulum for years, and I owned a savage pendulum.

They do work, follow the instructions and sight them in from the ground, then get up over 15ft and it is pretty accurate up to 30yds. After 30yds they are a little erratic.

What I didn't like about them was the noise...everytime I would shoot..a very loud vibration sound would come from my bow. This happened with both sights.

I now have switched a bought a single pin Impact Jumbo sight, I love it, its bright and very durable... and very quiet.