If the coax has CATV or CATVX printed on the outside it can be used in wall. There are 2 other markings CATVP for plenum or CATVR for risers. These can be used also but would cost more money for no benefit in this application. If you buy the cable off a spool, like at Home Depot and install your own ends, it should have the first 2 markings. If it is a pre-manufactured cable I would double check and see if it is approved. Good Luck