I know the ret' you mean John. I think it's marketed for HMR scopes, I've a couple and it works well as a holdover point with a zero at 25yds. I think (depending on manufacturer) it gets branded as the 'dual x' ret' or 'multi x ret'.
If I go on a standard 30/30 ret' with my .177", the base of the hair is perfect at x7 mag for the bucket at the hollow with a 25yd zero.