This is the standard shock cord used on the CC11-100 and CC11-160. 2ea per shock assembly are required. 4ea for a complete ship set. Per the Replacement Times chart in Section 6.3.1 page 2 of the CC11-100 and CC160 maintenance manual the shock cords are listed to be replaced every five years or in the notes column it states "Replace more frequently when bungees are no longer strong enough to return the landing gear to its stops or whenever they are frayed or damaged."