CultiBox Open 300 XL is a large indoor grow tent measuring 290 x 290 x 200 cm. The Open series emphasizes full access: three sides unzip completely and a large rear door lets you work deep inside the canopy without removing plants. The interior uses high-reflectivity diamond mylar to improve light distribution, while the thick, lightproof outer fabric and robust zippers help contain light. The 300 XL includes four adjustable ventilation ports (approx. 325 mm / 13 in), four cable outlets, passive mesh vents, and a removable waterproof floor tray for easy cleaning. Its sturdy frame and hanging straps accommodate heavy carbon filters and multi-light setups. Suited to advanced, high-capacity gardens that need space and convenient maintenance.