Trex ADA Handrail
Trex ADA handrail is not a guard and does not replace one. A guard stops you falling off the deck. A handrail is the round rail you grip on stairs. Separate requirements.
When you need one. Under the 2021 IRC model code a flight with four or more risers takes a graspable handrail on one side, 34" to 38" above the nosings. Adoption varies by state, so confirm with your building department.
A composite top rail is usually too wide to qualify, which is why this is a separate rail. Priced online. Call (815) 439-3325 for a flight count.