The Isle of Man has its own circulating coinage, which is used in parallel with the British Pound Sterling; it also issues an extensive range of Non-Circulating Legal Tender (NCLT) coins for collectors, as well as bullion coins in a variety of formats and designs.
The coin format most popular with collectors is the Crown, which has the same specifications as the British (decimal) Crown - also issued as a collector coin, and historically is derived from the British pre-decimal Crown, which was a circulating denomination.
After decimalisation, a Crown coin was nominally denominated as 25 pence, an old Crown being equal to five shillings, and a shilling re-denominated as five pence. The UK Crown and its derivatives - such as the Manx Crown - was later re-denominated as £5 in 1990. The Manx Crown displays the denomination as "Crown" though and not as £5 (which its UK counterpart almost never does), and is - also unlike the UK Crown - subdivided into fractional denominations, such as half-crown, one-tenth Crown etc.
This commemorative Crown coin marks the bicentenary (200th anniversary) of American Independence. | 
Search for Isle of Man: One Crown 1976 American Independence on eBay 