In Syria rebels and government forces both appear to be using the American BGM-71 TOW (Tube-launched, Optically-tracked, Wire-guided) anti-tank missile. The Syrian forces, however, must be using the Iranian copy of TOW, the Toofan. This first appeared in 2000 and by 2010 the Iranians had also copied some of the most recent American TOW missile designs. Iran first obtained TOW in the 1970s by purchase and the last time in 1985-6 as part of a secret (for a while) U.S. government deal to gain the freedom of American civilians kidnapped by pro-Iranian Islamic terrorists in Lebanon. By the 1990s these 2,000 TOW missiles had been used or had become too old to be reliable. Normally TOW missiles have a 15 year shelf life. It’s less than that if you do not have access to the proper maintenance equipment and spare parts. The TOWs that Iran received via Israel in the 1980s were already a few years old when Iran got them. Nevertheless the TOW technology was not all that advanced and Iran got foreign help (official and otherwise) that enabled them to produce the first TOW clone, Toofan 1, in 2000. By now the Iranians are up to Toofan 5, which is apparently close in performance to the TOW 2B. There is also a wireless (laser guided) version of Toofan and a version optimized for use against helicopters.
The Syrian rebels of the FSA (Free Syrian Army) received twenty TOW launches (MGS, Missile Guidance Set) and an undisclosed number of missiles in April. A second shipment was delivered in early July.
The BGM-71 TOW missile has been in service since the early 1970s. There have been many new and improved competitors developed, but the originals (somewhat upgraded) continue in service, production and demand. The Toofan, however, is the only direct copy. There are so many TOW launchers and missiles out there that it has become big business to refurbish and upgrade both launcher and missiles. That is a lot cheaper than buying new missiles or missile designs and with TOW you know what you got and are comfortable with it. The Toofan is compatible with the TOW launcher.
TOW has been in service since 1970, and over 500,000 missiles have been manufactured. Production numbers for Toofan are unknown, but probably do not exceed a few thousand missiles. All versions are shipped and fired from a sealed launch tube. That tube is placed on a MGS that contains the gunner sight, with night vision, and operator guidance electronics. The MGS weighs 25 kg (55 pounds). The 1970 version of the missile weighed 19 kg (42 pounds) and had a 3.9 kg (8.6 pound) warhead. The Toofan 1 was roughly similar to this. The latest version (TOW 2B or BGM-71F) weighs 22.7 kg (50 pounds) and has a 6.2 kg (13.5 pound) warhead that can defeat ERA (Explosive Reactive Armor). The Toofan 5 is similar to this one.
The last time TOW destroyed tanks was in 2003, during the Iraq invasion, but it was since been used frequently against enemy strongholds in Iraq and Afghanistan. There may have been some recent tank kills in Syria, where the rebels have received some TOW systems from the United States after the Syrian and Hezbollah forces were seen using the Toofan. TOW has gotten high praise from operators throughout its four decades of use and appears to have a decade or more of life left in it, at least on the ground. In the air TOW has largely been replaced by Hellfire, which came into use in the 1980s and has undergone several improvements. There are also several more recent and smaller missiles that are displacing Hellfire. TOW was innovative for the 1970s but has not been able to evolve fast enough to eliminate the market for new designs.
One things that distinguishes TOW from later designs is that more recent missiles are wireless. This has not proved to be as critical an innovation as many thought. There have been several wireless versions of TOW. Raytheon's radio controlled TOW was developed for use on AH-1 helicopter gunships, and the Saudis bought over a thousand of these wireless (RF) TOWs for ground use by their National Guard (a tribal militia formed to protect the royal family). There were other wireless TOWs. Work on such missiles dates back three decades. But the U.S. Army never adopted any of them. Israel developed its own wireless version (MAPATS or "Laser TOW") in the 1980s. The Israeli TOW uses a laser designator and still has a range of 4,000 meters. MAPATS weighs 29.6 kg (65 pounds) and evolved into a different missile in the 1990s. The Raytheon wireless TOW was lighter than MAPATS but still had a range of only 4,000 meters.
The thing TOW has going for it is reliability. It gets the job done, with either the wire guidance or later wireless models. It is a simple, precise and relatively cheap weapon that has constantly proved useful in combat.