This is really a car accessory that's been modded to make for an easy connection to a bike. The easy connection is its downfall. It can push out a lot of amps, so it really needs to be wired through a relay. Use an ignition switched source - tail light or parking light - to call the relay and wire the adpator through a line fuse. Again, for a bike I'd wire a single auxillary socket and plug the car version of this in to it if you ever need the multiple outlets. For convenience, use a 2 pin marine connector on the bike wired through the relay as described by ZX6RNewbie, and a car socket for in-dash fitting (very cheap) will have a pair wires that you can fit to the male part of the connector so you can just plug it in when you use the tank bag and auxillary socket. Be carefull of heat build up around this type of socket if it's inside a tank bag. On top of the tank is not somewhere I'd be comfortable with a fire starting.
I'll repeat. Don't wire an auxillary socket direct to the ignition switched source. These are built for about 5W, or less than 1A current. This socket can pass 15A. That will take out the wiring. Wiring it through the pigtails of a battery tender is also pushing it, as these only normally carry a few amps, but more important is that using battery tender pigtails you can accidentally leave stuff connected when you're off the bike, flattening the battery.
For USB only there's a nice little USB socket that someone posted in another thread. I fitted one to the Street Triple and it's great for charging phones, but my Navman Sat Nav sees it as a USB connection rather than a charger and won't work with it.