CC-5415 is a mt+ Chlamydomonas strain with the nit1 agg1 mutations. It’s also known as Witman g1. It was chosen for the CLiP2 library because it has a cell wall, it has strong negative phototaxis, it swims well, and it propagates well robotically. Below is the strain page at the Chlamydomonas Resource Center:

It comes free with every CLiP mutant order - you don't need to order it separately.