To many American troops, the thumb-size stick is known as the "Godpod" or "chaplain-in-a-box."
The Military BibleStick, created by an organization known for producing audio Bibles in languages with no alphabet, contains a dramatic reading of the entire New Testament and selections from the Book of Psalms.
"Listen Up," says the card that a soldier receives with the audio player. "Deployments can be tough. You temporarily trade everything you know -- your family friends and home -- for unknown challenges.
"You also have more time to reflect, to worry and to debate life's BIGGEST question. What you have in your hands can help ... God's Word can inspire and bring hope comfort and protection."
Over the last five years, 300,000 of the devices have been given free to American soldiers overseas. Funding is provided by churches of more than 120 denominations.
The Rev. Ronald Breight, pastor of Christ Lutheran Church in Forest Hills, Pa., got a Military BibleStick brochure in the mail several years ago and "thought it was pretty cool," he said.
Each Sunday before Memorial Day, his congregation takes a collection for the Lutheran Church-Missouri Synod's Ministry to the Armed Forces, and it opted to collect for BibleSticks at the same time. Each collection basket has brought in more than $400, he said.
"It feels good to provide something for the service men and women and for their families," said Breight. "It's the Bible. It's the good book."
Retired Col. Norbert Archibeque of the New Mexico National Guard used to personally offer them to soldiers as they boarded flights overseas. His stint as a commander in Afghanistan convinced the colonel, an ordained deacon in the Catholic Church, that having a strong faith made soldiers more resilient.
"The conditions there are austere, and the troops needed a lot of patience to work with the Afghan National Army," he said. "It wears on everybody, but it seemed like those without a deep sense of spirituality would get angrier. They would get very short-tempered with the Afghans, while the ones with the deep spirituality could deal with the ... changing environment."
So when his brigade chaplain showed him a Military BibleStick, "I told him that we had to get the sticks and put them in the hand of every soldier that we sent out the door," he said.
Archibeque stood beside his chaplain as the troops prepared to board transport planes for overseas and offered a BibleStick to each of them. Not one declined, he said.
"It gave them something to listen to and, in my terms, it strengthened their faith and brought them through long, difficult deployments," he said. "The BibleStick was a wonderful gift for the soldiers."
The Military BibleStick, powered by an AAA battery, is a dedicated device similar to an iPod, but its content can't be changed. The standard 19-hour version has the New Testament, with a soothing musical sound track in the background. Six hours of psalms, chosen for relevance to soldiers, were just added to a new edition.
"We went through the (Book of) Psalms and looked for ones that were uplifting and encouraging," said Bill Lohr, a spokesman for Faith Comes by Hearing, based in Albuquerque, which produces the BibleStick.
Most use the English Standard Version, a translation done with easy listening in mind, but King James and Spanish versions are available on request. Faith Comes By Hearing is seeking rights to a Catholic translation, the New American Bible.
Faith Comes by Hearing, a name taken from the New Testament book of Romans, produces audio Bibles in 733 languages, some with no written form. Overseas missionaries know it best for a device called the Proclaimer, which uses solar power and a hand crank to broadcast the Bible to assemblies of up to 500 people.
In 2006, Faith Comes by Hearing produced its first BibleStick for more technologically adept mission fields. They were bright white, had a glowing power indicator and were recharged by plugging into a USB port.
But military chaplains gave them mixed reviews.
"They said that these things are really great, that all our young soldiers do is listen to things and they're using them on base. But it doesn't work overseas," Lohr said. The gleaming white finish and light created a target. And the military didn't approve of plugging any outside device into one of its computers.
So Faith Comes By Hearing adapted the BibleStick for war zones. It has a matte-black finish, a tiny red light that blinks every 30 seconds and is powered by an AAA battery.
Production began in 2008 and distribution just passed 300,000. The military version can't be bought but is given free to troops courtesy of churches that raise money to cover the $25 cost.
More than 1,200 military chaplains have requested them.