He was looking for a 15-meter cable. Some areas are getting up to 2,000 Mbps via cable internet. Some very limited areas are getting 5,000 Mbps via telephone company internet. But that's not really the point. The overall quality of the cable is what matters. Good shielding too.
Yeah lets assume OP is getting 2Gbit to 5Gbit connection and is part of the %1 I was talking about. Then it would make sense for them to get a Cat6, still not "cat7" like you recommended because it will be due for upgrade in few years.
48 minutes ago, Billbill said:
Might as well buy cat7 and not have to upgrade in a few years.
IF OP is going to be running ethernet cables zip tied to power cables then sure getting a STP cable would be the way to go. In any other case regular UTP Cat5e is more than sufficient upto 100 meters. If their network setup and their internet bandwidth is going to be more than 1GbE, and the cable is going to be run over the distance of 100 meters, Cat6 is the way to go.