This is a brand new, nicely-made reproduction bonnet mascot, correct for Jaguar saloons made between about 1950 and 1968, including Mark I, II (2), 3.4S, 3.8S, Mark VII, VIII, and IX. These large (a little under 8 inches long) leapers were often fitted to XK120, XK140 and XK150 cars when they were new, usually by the dealer.
This one is very nicely made, with good detailing and flawless chrome.