One Shot

It is usually made of rubber, wood and aluminum. In Afghanistan, craftsmen hammer it together using spent artillery shells. In Cambodia, part of it's rubber components are scavenged from truck tyres.
The story behind the very first design is that a sculptor riding his bicycle got a flat tyre and went to a repairman. The repairman was busy retreading a truck tire with vulcanized rubber, and seeing this, the sculptor got his idea for the ___________.
There were only 59 such __________ being used from 1968 to 1975 but they became popular and were put to much wider use after the Afghan war in the late 1970s. Presently, _________ is sold for around $35 while other competing products(?) cost about thousands of dollars. _______ was never patented.
Source: TIME Magazine Article on _________.