Nerf Bars aka Nerf Steps for trucks and SUVs are essentially tube-shaped, sometimes oval or round side steps that mount under the doors, normally to the underside rocker panel or frame providing a convenient step to get into and out of a today's modern vehicles which are normally quite high up. Nerf bars or nerf steps are typically made of durable materials like stainless steel, carbon steel or aluminum. They offer a more rugged, classic truck look compared to regular running boards and can also provide good protection against rocks and road debris, along with a convenient step to access the truck bed or roof.

Key Characteristics and Functions:

• Step up in for easier access: The primary purpose or nerf bars is to provide a secure step into and out of the truck or SUV, especially for taller vehicles. 
• Tubular design: Unlike the wider flater boards of running boards, nerf bars feature a round, oval, or rectangular tube design offering an attractive look and excellent functionality. 
• Grip and traction: Many nerf bars include integrated rubber or plastic step pads for added grip and slip resistance. 
• Protection: They offer good protection for the truck's rocker panels from rock chips and other road debris. 
• Aesthetic appeal: Depending on the brand and exact type, nerf bars generally offer a rugged, classic, or off-road-inspired look for the vehicle. 
• Material and durability: Typically constructed from high carbon steel, stainless steel or aluminum, these bars are designed to be very strong and long-lasting. 
• Length: They can run the length of the cab or can be ordered for wheel-to-wheel application.