Pipers Cove has an extensive kilt rental division featuring four different tartans: Royal Stewart, Black Watch, Muted Dress Macdonald, and the Irish National Tartan, which was designed by "Pipers Cove" and "House of Edgar" at the request of our Irish customers wishing to have a distinctive tartan incorporating the key Irish colors.
Quote from Piper's Cove Website - Obviously they acknowledge it is with House of Edgar, and if Stillwater has an agreement with them, there is no problem.