Got one of the same , plain old fashion burris ballistic plex. 4.5-14 E1 , going on a "custom" ceracoat AR she designed (what parts what colors she wanted) in 6.5 grendel. Have the same place in an older fullfield II , like it.
The other "unattached tree plex " I have in a 6.5-20 E1 it's fun for shooting games and targets , but too small thin for hunting in any kind of low light conditions.