"I can't comment on reliability, but just like the other cheap vents from screwfix, the flap that is supposed to prevent the wind blowing back into the house just rattles open and closed in the wind. Very irritating."
"This product was purchased to allow trickle venting of moist air from a room to the outside. The product picture in the catalogue seemed to show a grille on the entrance to the canopy. Once purchased it was evident that their was no vent just an open hole. So flies and creatures could enter the room via the vent or use the cover as a home. I had to fit a fine mesh to prevent this. Fortunately my DIY skills allowed me to get a satisfactory solution and finish. Others may not be so lucky.. Pity Manrose don't have an optional filter to fit in these vents for all the range maybe purchased separately. One size for 100mm and another for each of the tubes sizes in the range as an assessory. Time was some manufacturers did have a filter either as part of the Vent or as a fit and forget square behind the grille. etc.."