I personally carry a couple of very short length, 4" to 6" crossover and rollover Ethernet cables. Each has a RJ45 coupling attached. With these cable/coupling segments I can put together a crossover or rollover cable of any length using available straight through cable. There are alway straight through cables laying around. Additionally, the small size of these cable/coupling segments makes them easy to pack up and store. They have come in handy many times.