Mastercraft® Metal Newel Mounting Plate with Screw Pack at Menards®
Newel Mounting Plate - Etsy
Wrought Iron Newel Post Mounting Kit - Affordable Stair Parts – Affordable Stair Parts®
RELIABILT 4.625-in x 4.626-in Ezlock Plate Newel Fastener Finished Stair Newel Post in the Stair Newel Posts & Installation Kits department at Lowes.com