Retna lock bowsight add on

[The big greasy]

The iq retna lock bow sight has the round circle and to show your form is correct it has this little black dot one makes sure is in the center of the green dot. My question is does anyone make this so one can mount it on any bowsight? I thought I seen it a few years ago, or something like this. I know one concentrates on form, it’s just a little assurance. Thanks.