This is a blank truss rod cover for a recording king RK 30 BGM. These are customisable using text in studio to stick your name on i recommend ar berkley thickness .5 with embed .5 on it. I'll upload another profile perhaps with this on. holes are 42mm between centres. I expect this will be able to be resized by 1-2 mm to make a new size for other brand of banjo's although  i haven't tried it. If you send me the make and size between centres I could add one with a changed distance between centres on my fusion model.