Ubbink's UB11 (380mm x 285mm) is an in-line unit with a multipurpose base which will provide inconspicuous ventilation in natural and manmade slate roofs. Can be installed with either 500mm x 250mm or 600mm x 300mm slate vents.
Ubbink's Vepac (382mm x 398mm) is an in-line unit which should not need trimming when installing with 600mm x 300mm slates.
                                
                                            -  In-line design 
 
                                            -  Soil/vent and mechanical extract adaptor available 
 
                                            -  High or low level roof void ventilation