It does what it's supposed to do (i.e. transmit low-current, low-voltage DC power over short distances).
Even at this low price, however, I think the construction and material choices leave a lot to be desired. Rather than using individually insulated two-conductor cable, the DC5 uses a single-core shielded cable. Not a bad choice in itself, but this prticular cable has a very, very thin core (with maybe 8 copper strands), and the core is connected to the negative side (assuming Boss-style center negative wiring).
As I said, it does work, but I'd recommend trying something else first.