Reddiseals trickle vents are supplied in packs and include vent and canopy, or vent, canopy and grill. Surface mounted or flush fit styles are available. All our window trickle vents comply with part F of the building regulations for new build and replacement. We offer a slimline vent for sash windows. The Link Vent Trickle Vent meets the requirements of the building regulations for newly installed windows.