The cleverly designed shape means the sloping lids on both sides not only create an excellent sun trap throughout the year but also allow maximum use of the space provided. Smaller or younger plants can be placed near the 8" high front and back edges, whilst larger specimens up to 2' high can be grown in the centre of the frame. Ventilation & Access - aluminium locking brackets with two opening positions enables the frame to be left securely open for excellent ventilation. Lower position allows air in whilst providing good protection from the elements; the top position is for maximum ventilation. Top panels can be fully opened to allow plants to be easily lifted in or out of the frame & allow easy watering.