Titan Building Products - 4x4 Wood Post Anchor Kit - TIPRG441 - Galvanized - Fasteners included - 3.5" to 4" square railing posts Amazing finished appearance with anchor hidden deep inside post Fast and easy installation on any surface-No notching deck boards Post stay drier and last longer Tested and approved against AC273 for use with US residential wood guard rails Includes all required galvanized fasteners