Around here, we call Tony Dixon's aluminum high d The Modern. Traditionally, whistles had thin walls which leant towards their "tin whistley" tone (if that's a word :). In more recent years, many makers, perhaps starting with the late/great Bernard Overton, began making Irish whistles with thicker walls, which produced a more substantial/solid tone. We still love the traditional thin-walled sound, but sure do love the solid tone that The Modern provides.
New students to Blayne's online tin whistle and Irish flute lessons get this whistle for free when signing up with the annual billing option. Just mention to us that you've signed up and we'll send you one on the house!