This Holt Allen drain plug was used on LP boats built 1998-2001. Gray. Screw-in hole spacing matches the RWO bung - Assembly mounting hole is slightly larger than the RWO (should fit without enlarging existing hole). Bung is captive. Seals with rubber O-ring. Sold as an assembly only (replacement bungs are not available separately).
Mounting hole measures 1 in (25mm).