DOMETIC HEKI Mini Heki Plus Rooflight 400 x 400 with Ventilation for roof thickness 25- 42. Suitablefor Caravans. Featuring an easily adjustable fly net and blind for ultimate shading and pest control, the Dometic Seitz Heki Style roof light provides great thermal insulation and protection from the elements thanks to its proven Duette Honeycomb system.