Some rooms sit beyond roof access. The **SunTube25 side wall** routes daylight horizontally through a highly reflective tube so basements, internal corridors or protected façades gain natural light without conventional glazing. A crystal glass dome captures and cleans daylight on the exterior, while the insulated wall box and mirrored elbow maintain brightness through the turn. The easy‑click diffuser softens output to a comfortable glow that feels natural across the day. Installation is straightforward and airtight, and the module integrates with the wider SunTube system for extensions up to six metres or upgrades with EcoPower insulation when thermal targets are critical. Use **SunTube25 side wall** to unlock windowless spaces—compact aperture, convincing light levels and a finish that reads like a discreet, built‑in luminaire.