By Tarik Kafala
BBC News Online
Though rudimentary and ineffective, Hamas' Qassam-2 rocket is seen by Israel as a very serious threat.
This rocket landed on the outskirts of Ashkelon
In theory, the rocket brings Israeli population centres into the range of Hamas - just as Hezbollah fighters in southern Lebanon were able to target towns and villages in northern Israel.
Yet the rocket, first used in February 2002 against a target inside Israel, has caused very few casualties and very little damage. One estimate suggests that in approximately 2,000 firings of the rocket no-one has been killed.
For their own reasons, Israel and Hamas seem to be playing up the danger that the rocket poses - Hamas can trumpet its military effectiveness and Israel has further arguments to justify its raids into Gaza and the West Bank and its policy of liquidating Hamas members.
Israeli officials say the firing of Qassam-2 rockets by Hamas is a "red line" that will solicit a severe response.
On Thursday, four Qassam-2 rockets were fired into Israel from northern Gaza. As usual it caused no casualties or damage.
For the first time though, a Qassam-2 reached a major Israeli town, landing near an industrial estate in the costal town of Ashkelon. This was the furthest north into Israel the rocket has reached.
Soon after a member of Hamas' military wing was killed and three others injured by missiles fired from an Israeli Apache helicopter.
Made by Hamas' military wing, the Izzedin al-Qassam brigade
First launched against Israel on 10 February
Range of 10 to 12 kilometres
Estimated 2,000 firings, no deaths
Eight Israeli tanks and two armoured personnel carriers moved into northern Gaza and levelled shrubbery the Israelis believe was used to hide the militants who fired the rocket.
Until the end of June, Israeli forces had occupied the northern Gaza town of Beit Hanoun, officially in order to prevent Hamas from firing their rockets.
Reports describe widespread destruction in the town. Dozens of homes were levelled, factories torn down and vegetation pulled up.
Palestinians say this tactic has a dual purpose. It reduces the cover available to Hamas militants firing the rockets. It also makes part of the cost of the firing of the Qassam-2 payable by ordinary Palestinians.
Hamas' deployment of the Qassam-2 was expected to change the nature of its operations. Its ineffectiveness has meant that there has been no strategic shift and Hamas still depends on suicide bombings.
If the missile is used and deployed effectively by Hamas, Ashkelon would be in easy range of Gaza and Tel Aviv in range of the West Bank.
For groups such as Hamas, the example of Hezbollah is a very compelling one.
Hezbollah drove Israel out of southern Lebanon through a combination of inflicting heavy casualties on the Israeli army and Katyusha rocket attacks on Israeli towns and villages.
The Qassam-2 has, according to the Israeli army, a range of 10 to 12 kilometres (six to seven miles).
The rocket is launched from a pipe roughly a metre (yard) long and 120 millimetres wide using an explosive charge of four to six kilograms.
By most standards the Qassam-2 is a very primitive weapon. However, the rocket's ease of assembly and low cost are part of its appeal.
It is believed that the Qassam-2 can be launched by a timer, allowing Hamas militants to avoid being hit by the Israeli response to the launching of the rocket.