In the 21st century the cable jetting technique is used worldwide, from small optical telecom cables (1.8 mm diameter) in small microducts (3 mm internal diameter) [http://www.rala.se/products.asp up to large copper telecom cables (35 mm diameter) in large ducts (50 mm internal diameter). Jetting is done with a pressure of the compressed air in the order of 10 bar. With the jetting technique distances per blow of 3.5 km have been reached [https://web.archive.org/web/20060322211338/http://fibers.org/articles/news/7/9/2], while spliceless links of 12 km have been reached by placing jetting equipment in tandem. It is possible to install 12 km in one day with one small crew.