"We don't have rocket launchers, but I can make a bomb out of practically anything," says a proud Abu Hudeifa, a university dropout turned member of a jihadist group fighting in Aleppo, northern Syria.
"I connect two cables to the vehicle battery, and when they make contact ... boom!" says the 24-year-old, who confesses a deep hatred for President Bashar al-Assad, as he shows off an old Russian-made rocket mounted on a pick-up truck.
Born in the town of Marea in Aleppo province, which has seen fierce fighting between rebels and regime forces for several months -- Abu Hudeifa has joined the Al-Nusra Front, blacklisted by Washington as a "terrorist" group.
He, however, bears no anger towards the United States and the focus of his hatred is clear.
"I don't hate the United States or the West... I just want Assad to leave my country and to stop killing people. That's why I joined Al-Nusra," he tells AFP.
Not much is known about Sunni Al-Nusra Front except that it is a jihadist group with roots in Iraq and has claimed some of the deadliest attacks against Assad's forces in the conflict roiling Syria.
Analysts say the group believes that the fight against Assad is a religious struggle to oust a regime dominated by members of Allawite community, an offshoot of Shiite Islam to which the president belongs. Some 80 percent of Syria's population is Sunni.
Many also believe that for months now Al-Nusra Front has been spearheading the anti-Assad rebellion even as the main rebel Free Syrian Army struggles to overcome divisions in its ranks.
Abu Hudeifa, who learnt his bomb-making skills from his older brother Ammar, says he joined the Islamist group for its adeptness at combat and not for its extremist ideology.
"Thanks to Al-Nusra, we will win the war ... only Al-Nusra is ready to fight to the death."
Ammar says his younger brother is only a fighter like him and not an extremist, like other members of Al-Nusra Front.
"My brother is much more open-minded than all the men in his group. He is no radical...He's just a fighter, like me," says Ammar, 28, who himself is a member of a mainstream rebel group and has swapped bomb-making for filming battles.
As children, Abu Hudeifa and Ammar spent long hours taking apart and then fixing remote-controlled car toys or any gadgets they could lay their hands on.
"I've always been good at fixing things," says Abu Hudeifa.
"When my mother's washing machine or fridge stopped working, or when my father's car broke down, I'd get my toolbox out and get working... Now my brother and I put our knowledge to practice in war," says Abu Hudeifa, who has sharp features and a short beard.
The brothers take great pride in their inventiveness, which however, has not been without cost. Abu Hudeifa has lost three fingers when a small plastic explosive blew up too early.
"We've made devices from scratch. I've made remote-controlled bombs that exploded as army vehicles drove past," he says.
"We've also packed pressure cookers with explosives. We close them tight with screws, heat them up for hours, then lay them on the road. When they explode, the cooker breaks up into shrapnel.
"They're very effective. We've even managed to destroy many army vehicles' armour that way," Abu Hudeifa says.
The two brothers share a raging hatred towards Assad for very personal reasons.
Ammar's wife was killed instantly when a rocket fired by regime soldiers struck the car she was travelling in.
"I'll never forget my brother's face when he heard his wife had been killed," says Abu Hudeifa.
The two also share the pain of being separated from their parents who fled their home for neighbouring Turkey when violence swept northern Syria.
"I want revenge ... I want to make Assad pay for my parents' misery in a refugee camp across the border. They are freezing to death," says Abu Hudeifa.
"I'm tired of watching friends and family being buried."