PHILADELPHIA -- A man pleaded guilty to weapons of mass destruction charges for sending a mail bomb to a Chicago surgeon he said botched his penile enlargement surgery, though his attorney questioned whether the charges fit the offense.

Brett R. Steidler, 25, of Reamstown, Pa., mailed the explosive device in February 2005 because he was "extremely unhappy with the results" of the $8,000 surgery, Assistant U.S. Attorney Jennifer Arbittier Williams said in court filings.

Reamstown is in Lancaster County.

But Steidler alerted authorities before the bomb arrived and it was retrieved from the mail and disarmed.

His attorney, Luis A. Ortiz, said Steidler is mentally ill and noted the difference between the roughly 2-year sentence for mailing a letter bomb and the 4- to 8-year sentence for using a weapon of mass destruction.

"You shouldn't group this guy with people who drive truck loads of explosives to buildings or gather anthrax or do things for political reasons," Ortiz said.

Sentencing is scheduled July 7 before U.S. District Judge Lawrence F. Stengel.