The bat that hammered the final nail on the House that Ruth Built is for sale.

Babe Ruth's (search) famous lumber — the very bat with which he homered on the opening day of Yankee Stadium — will be sold at Sotheby's on Dec. 2.

Sotheby's expects the so-called "Holy Grail" of sports to soar well over the $1 million wall.

"Only two other pieces of sports memorabilia have done that," said Sotheby's spokeswoman Lauren Gioia, referring to a 1909 Honus Wagner baseball card (search) ($1.265 million) and latter-day Sultan of Swat Mark McGwire's (search) 70th home-run ball ($3 million).

The sale of the bat will take place at Sotheby's auction house as part of a larger sale being coordinated by SportsCardsPlus, a memorabilia company.

Other lots in the auction are the Bambino's last will and testament, one of his baseball gloves, the first baseball that Mickey Mantle (search) ever hit for a home run, and Lou Gehrig's (search) signed 1936 contract.

But the Bat that Ruth Used is getting all the attention.

"The Babe Ruth bat," said David Kohler, president of SportsCardsPlus, "is simply the finest piece of sports memorabilia in the world. Virtually everyone who sees it is simply blown away, not only by the mere existence of the bat, but also by its incredible beauty. It has a definite aura about it."

A crowd of 75,000 was on hand — and 25,000 were turned away — on Opening Day at Yankee Stadium, April 18, 1923, when Ruth homered to help the Bronx Bombers (search) defeat the hated Boston Red Sox, Ruth's former team.

After that historic Opening Day in the Bronx, Ruth donated the bat to the Los Angeles Evening Herald, to be awarded to the winner of a high- school home run contest.

"To the boy home run king of Los Angeles," he inscribed on the bat. " 'Babe' Ruth, N.Y., May 7, 1923."

The paper awarded the bat to Victor Orsatti a month later. The bat has stayed in the family ever since. Orsatti died in 1984.

The winning bidder will also receive the congratulatory telegram Ruth sent to Orsatti on his home-run prowess.

The bat and some items from the sale began a three-day exhibit at The National Sports Collectors Convention in Cleveland, Ohio, yesterday.

New Yorkers will finally get to feast their eyes on the bat from Nov. 27 to Dec. 1 at Sotheby's.