Why are NFL players wearing padding on helmets at training camp?

Bengals linemen, linebackers and tight ends wore Guardian Caps at training camp after the NFL required the padding for some position players this preseason.

Puffy Guardian Caps Could Reduce NFL Player Concussions

Browns wearing Guardian Caps during training camp

Why are NFL players wearing padding on helmets at training camp

NFL Mandated Guardian Caps: Controversial Change - Sports

Guardian cap' to prevent head injuries mandated for practices, CFL says

NFL's use of Guardian padded helmet caps in camp draws support and skepticism - The Athletic

nfl helmets training camp

Guardian Cap Use a Concern for Watt, Saleh Early in Training Camp - Sports Illustrated

Why are NFL players wearing padding on helmets at training camp?

Carolina Panthers NFL helmets training camp

What are those funny-looking soft caps on NFL helmets during camp?, Sports