DY protective outer cableshttp://www.dycables.com/car-brake-outer-casing-products-i-284.html combine a metal spiral with plastic. They protect DY Flexible shaft and Inner wire from environmental influences such as dust, dirt and moisture and also offer improved guidance. Additional benefits of using a outer cables.
The outer cables are abrasion and temperature resistant and also resistant to many acids and lyes. The standard colour is black, we also can produce other clour. 
According to the experience, the outer cable inner diameter should be 1/3 - 1/4 larger than the flexible shaft and inner wier diameter.
