maximum speed in 3.5 Mach. A total of 150 built before the program ended and the subsequent withdraw of HQ-3 from active service, and the knowledge gained from HQ-3 was used to develop later version of HQ-2. HQ-4: Further development of HQ-2 from HQ-3, with solid rocket engines, resulting in a two-thirds reduction of logistic vehicles needed for a typical SAM battalion with six launchers: from the original more than 60 vehicles for HQ-1/2/3 to just slightly over 20 vehicles for HQ-4. After 33 missiles were built (5 from batch 01, 16 from batch 02, and 12 from batch 03), the program was cancelled, but most of the technologies were continued as separate independent research programs, and these technologies were later used on later Chinese SAMs upgrades and developments such as HQ-2 and HQ-9. Sayyad-1: Iranian upgraded version of HQ-2 SAM differ with the Chinese versions in guidance and control subsystems. Sayyad-1 equipped with an about 200-kilogram warhead and has speed of 1,200 meters per second. Sayyad-2 Sayyad-3 Sayyad-4 Sayyad-4B DF-7 DF-7/Dongfeng 7/M-7/Project 8610/CSS-8: Chinese surface-to-surface tactical ballistic missile converted from HQ-1/2/3/4. M-7 missile is the only Chinese ballistic missile that can be launched at a slant angle. The rear section of the HQ SAMs are retained, but the forward half is greatly enlarged into a shuttle shape to house bigger warhead and more fuel, while the control surfaces on the forward section are deleted. Armed with a 500 kg warhead (two and half a time of that of the original SAM version) the maximum range of M-7 is 200 km (more than four times of that of the original SAM version). Qaher-1 The Qaher-1 (, meaning "Subduer-1") is originally a Soviet S-75 missile that was developed locally by the Houthis to be a surface to surface missile that works on two stages, liquid fuel and solid fuel. It was unveiled in December 2015. The Houthis have fired many Qaher-1s into Saudi Arabia during the course of the Yemeni Civil War. Operators Current operators - 40 – 79 Launchers – 25 – 18 – 240, Tayer el-Sabah variant – Some developed into self-propelled systems Tigray Defense Forces – 300+ Launchers, HQ-2J and indigenous Sayyad-1/1A & 2. – few – 48 next 250 in 2008 – up to 270 – HQ-2B in service with the Pakistan Air Force. – 700 – 275 – few – 280 Former operators Afghanistan – 84