Twin brothers who pleaded guilty to charges that they set off bombs in Chester and Lancaster Counties while on Christmas break from colleges last year were sentenced Monday to six to 23 months in prison, given three years' probation, and ordered not to have contact with each other for five years.

Daniel and Caleb Tate, 23, of Cochranville, were charged in connection with six incidents in December 2015 in which they detonated makeshift pipe bombs, five of which caused property damage. None caused injuries.

The sentence imposed in Chester County Court represented a "fair result for all involved," said Rob Donatoni, attorney for Caleb Tate. "It was a very challenging case .. in the present climate given what is going on in the country," he added, referring to anxiety over terrorist attacks.

When the brothers surrended in May on charges that included arson by explosion and criminal mischief, Daniel Tate had just graduated from Pepperdine University, in Malibu, Calif., and Caleb was still a student at Belmont University in Nashville, Tenn., a year from graduation, according to their attorneys.

The Chester County District Attorney's Office said the twins made bombs out of metal pipes, fuel containers, propane canisters, propane torch tips, and other materials.

The twins also were charged with retail theft. Video showed them shoplifting materials to make the bombs from local stores, the DA's office said, and some of the supplies were charged to a debit or credit card in Daniel Tate's name.

On Dec. 20, they blew up a mailbox at a residence on a rural, grassy road in Highland Township, Chester County, and two days later detonated a bomb in a wooded area in Londonderry Township, Chester County, authorities said.

They exploded a pipe bomb on Dec. 30 in Lancaster County in an Amish phone shed, an enclosed building with a phone used by multiple Amish families, who do not permit phones in their homes, prosecutors said. The explosion badly damaged the shed, Colerain Township.

On New Year's Eve, they set off a bomb that damaged an Amish produce shed in Strasburg Township, Lancaster County, authorities said. Later day day, they allegedly exploded another bomb in a well pump shed in West Fallowfield Township, in Chester County, also damaging that shed.

Both brothers apologized for the incidents.