RAMADI, Iraq — The 21-year-old gunner was standing atop the turret of a Humvee called Frankenstein's Monster when the bomb exploded on the ground beside him, sending a wave of sizzling shrapnel and ball-bearings toward his head.

Knocked down inside his vehicle by the blast, Spc. Richard Sugai regained consciousness minutes later and realized he was lucky to be alive. His savior: a glass cocoon of 2-inch thick bulletproof windshields he had welded around the top of his turret three days earlier.

Troops mockingly call the modification "Pope Glass" because it brings to mind the ballistic-proof glass box the late Pope John Paul II traveled in after being wounded in a 1981 assassination attempt.

The juryrigged protection has become a signature on the turrets of Humvees across the main U.S. base in insurgent-plagued Ramadi, where troops are adding ever-more armor to protect against snipers, small-arms fire and roadside bombs.

"I would have been gone if that glass hadn't been there," Sugai said. "I probably wouldn't have a head."

The Vermont National Guard's Alpha Company, 1st Battalion, 172nd Armor, became the first to start using the so-called Pope Glass after one of its support soldiers, 40-year-old Spc. Scott Betit, attached one to his Humvee after his initial run through Ramadi in late July.

"It was really uncomfortable keeping myself above the turret that first time. I felt exposed," said Betit, of Whitecreek, N.Y., while standing beside his Pope Glass-fitted Humvee, the gun-shield of which is painted with a red-scarfed Snoopy manning a machine-gun. "When I put the glass on, everybody was like, what the hell is this guy doing? But then they started asking for it."

It soon spread throughout Alpha Company and other units.

The added glass — fashioned out of three Humvee front windshields welded above the armored-steel ring around the sides of the gunner's turret — are roughly 18 inches high. Alpha Company commanders say the glass has spared seven gunners from either death or severe head trauma over the past six months.

Concerned about the constant threat of insurgent attack, extra armor is being added on everything that moves off base, including tanks, trucks, and tracked medical vehicles.

It's a far cry from the days of the 1991 Gulf War, when U.S. troops actually stripped down already unarmored Humvees, removing glass from side doors to avoid glare that could reflect miles across deserts, said Capt. Duby Thompson, Alpha company's 40-year-old executive officer.

Such thin vehicles are almost never used off-base now, derided among troops as "hillbilly armor." Today it's all about "up-armor" — adding on more.

The Army has shipped thousands of M-1114 Humvees to Iraq with specially armored doors and bellies and ballistic-proof glass. Though gunner turrets on these vehicles already are surrounded by a flank of armored steel, some soldiers feel their back and sides are exposed.

"Everybody going outside the wire should have it," said Thompson, of Danville, Vt. "I love the stuff. It saves guys' lives."

Sugai survived the bomb blast one morning in October. As his colleagues were inspecting the site of a previous blast, he was pulling guard duty, with his fingers on a 240 Bravo machine gun. The bomb, believed made of artillery shells strapped to a propane tank, exploded a few feet away, and the shock wave hurled Sugai from side to side, slumping him down inside the Humvee.

Minutes later, he awoke, patting his body parts to make sure they were still there. He suffered only a damaged eardrum, several minor scratches and a tiny pebble lodged in his eyebrow.

Shrapnel completely shattered one of the Pope Glass panes. The ballistic glass was replaced, but the Humvee's rear side is still peppered with two dozen shrapnel impacts.

Capt. Robert Beaudry, 37, of Milton, Vt., said Pope Glass had been added to nearly 100 Army Humvees in Ramadi. Motorpool mechanics have cannibalized existing stocks and added them to Humvees at request.

Some gunners have added wooden covers atop the glass to protect against rain. Others have spray-painted the glass black in some parts, so their heads aren't silhouetted.

Not all gunners like them. The panes add 400 pounds onto vehicles that already weigh nearly 10,000 pounds. That can make a Humvee harder to drive and more liable to roll over.

It hasn't been cheap, either. Each pane costs about $2,500.