Drain Socket Round w/ Captive Plug 40 mm White | 4BoatsWhite round drain socket with captive plug for 40 mm (1. 57 in) openings, designed for boat decks and drain fittings. Captive plug prevents loss of plug Round socket provides a neat, finished opening Suits 40 mm cut outs nominal 40 mm (1. 57 in) White finish blends with white deck fittings Easy to install in standard 40 mm apertures For boat decks and drain fittings secure, reliable drainage point