You're looking for a Series 3 button. Otis/Unitech makes them either 110 VAC or 24 (30) vdc. The locking ring is pretty slick. You can also interchange them very easily with standard 1 3/8" hole buttons. They sell a trim ring made of SS that fills the gap between the 1 5/16 Series 3 and a standard 1/3/8" hole. Minutes to install. No stud gun. As far as adding a second riser, fairly straight forward. The RS5 or 14 board doesnt care. Although you would use the 24 vdc model button.
