This is a 1997 Sir Donald Bradman tribute Postal Numismatic Cover (PNC). It includes a $5 bimetallic coin and two 45c stamps, commemorating the Australian cricket legend, Sir Donald Bradman. The PNC was released on January 23, 1997, and features a first-day-of-issue postmark from Bowral, NSW, Australia. 
Here's a breakdown of the components:
* $5 Bimetallic Coin: 
The coin features a depiction of Sir Donald Bradman batting on the reverse and the Maklouf portrait of Queen Elizabeth II on the obverse. 


* 45c Stamps: 
Two stamps depict Sir Donald Bradman, one with his portrait and the other with him batting, these stamps are part of the Australian Legends series. 


* First Day of Issue: 
The PNC is marked with a "First Day of Issue" postmark, signifying its release date. 


* Australian Legends Series: 
This PNC is part of the Australian Legends series, honoring notable Australians. 


The PNC is a collectible item that combines philately (stamp collecting) and numismatics (coin collecting), making it a valuable piece of memorabilia for cricket fans and collectors. It is considered a tribute to Sir Donald Bradman, widely regarded as one of the greatest cricketers of all time.