The HJC RPHA 31 Dereen MC21 is an open-face helmet designed with a Premium Integrated Matrix (PIM) Evo shell and multi-density EPS to support shock resistance and rider protection. Its aerodynamic shell was developed through wind tunnel testing to reduce air resistance, improve stability at speed, and help create a quieter ride.

The Pinlock 120XLT DKS467-ready HJ-39 shield provides 99% UV protection and features an anti-scratch coating. An integrated smoke-tinted sun visor with anti-fog coating deploys through the bottom-positioned operation system and offers multi-step adjustment, including positioning up to 10 mm closer to the face for personalized shading.

Full front-to-back airflow is provided by two intakes and four exhausts. The RPHA 31 also includes a shield holder designed to reduce noise and drag while keeping the visor secure. It accommodates second-generation SMART HJC Bluetooth communication systems, which are sold separately.

The RPHA Premium Fit interior uses advanced antibacterial fabric with moisture-wicking and quick-drying properties. Removable, washable crown and cheek pads, 3D contour cheek pads, interchangeable cheek pads across all sizes, reflective material, and an elongated shell with extended chin EPS support a customized fit and full face-level coverage. This Small-size helmet is identified by HJC part number JA19NUS4221V.

Features:

• Premium Integrated Matrix (PIM) Evo Shell: Uses Carbon-Aramid Hybrid and Natural Fiber reinforcement materials for shock-resistant performance, comfort, and lightness.
• Aerodynamic Design: Wind tunnel-developed shell reduces air resistance and supports stability at high speed.
• HJ-39 Shield: Pinlock 120XLT DKS467-ready shield provides 99% UV protection and has an anti-scratch coating.
• Integrated Sun Visor: Smoke-tinted, anti-fog sun visor deploys through a bottom-positioned operation system.
• Multi-Step Sun Visor Adjustment: Allows the sun visor to be positioned up to 10 mm closer to the face.
• Ventilation: Full front-to-back airflow is provided by two intakes and four exhausts.
• Quiet Ride Design: Shield holder reduces noise and drag forces while holding the visor securely.
• Bluetooth Compatibility: Accommodates second-generation SMART HJC Bluetooth communication systems, sold separately.
• Premium Fit Interior: Advanced antibacterial fabric provides moisture-wicking and quick-drying performance.
• Removable Interior: Crown and cheek pads are removable and washable.
• Customizable Fit: 3D contour cheek pads and interchangeable cheek pads throughout all sizes support fit adjustment.
• Reflective Material: Reflective material supports visibility.
• Full Face-Level Coverage: Elongated shell and extended chin EPS provide encompassing coverage.
• Size: Small.
• Part Number: JA19NUS4221V.