Expanding Drain 40 mm Expanding Plug, Black | 4BoatsBlack Expanding Drain plug from Expanding Drain seals 40 mm (1. 57 in) boat drain apertures; compact, low profile and easy to fit on board. Expanding mechanism for a secure hold in hull apertures Fits 40 mm (1. 57 in) drain holes Black finish for a discreet, low profile appearance Sealing face prevents water ingress when fitted Compact size easy to stow on board Simple to fit and remove without tools Durable construction suitable for marine