NEDERLANDSE TANK-EN PAKETVAART MAATSCHAPPIJ N.V.
image by Jarig Bakker, 1 February 2001
Wyt suggests a darker funnel colour for N387, probably also applicable to N221.
Westertoren confirms this funnel. The flag colour is guessed from an account that groups orange and yellow together; Rosanoski considers the result suspect.
Bakker’s flag follows the Dutch house-flag chart issued with De Blauwe Wimpel in April 1956.