What are Extraordinarily High Relief Coins?

By GovMint :

Extraordinarily High Relief (EHR) coins are coins created with a special striking technology developed by the Royal Canadian Mint (RCM) that results in exquisitely sculpted coins whose designs tower above their surfaces, much more than standard, High Relief (HR) or Ultra High Relief (UHR) coins. Some examples of recent Extraordinarily High Relief coins issued by the Royal Canadian Mint include the Multifaceted Animal Head: EHR Wolf Coin, whose designs tower 6 mm over the coin's surface, and the RCM's 2024 "Year of the Dragon" coin, which showcases EHR on both sides, with the dragon design raised to an impressive height of 4.7 mm.

Sources Used:

https://www.mint.ca/en/company/media-room/2024-02-06-the-royal-canadian-mint-breaks-new-ground-with-double-sided-extraordinarily-high-relief-on-gold-and-silver-year-of-the-dragon-coins