If you put up a link or picture, it is not showing up for me. All I can say is the Cortech makes VERY reliable products as longs as you make sure the bag will fit. As I told in another thread I have a Bilt Magnetic Tank Bag V2 which is pretty darn small. It has worked great on my V650, not sure about how it would fit on 300, but they don't get any smaller than this one. Good Luck.
I can't speak to anything specific to the magnetic version, but I have the strap mount version and just used it on my 650 this weekend for touring around Sonoma and the Northern California coastline. Pics here if you are interested - the first shows it in 18L expanded configuration, the others in the 12L compact setup. Either way was fine, but it seemed slightly more wobbly when expanded, so I'd suggest making sure the heavier items are in the bottom close to the tank and only lighter objects stuffed toward the lid of the bag. But I second the above opinion about the good quality of Cortech products. I used to have their saddle bags on a past bike and they held up well despite the beating I gave them - right up to the point where some scavenger managed to find a way to rip them off one night while parked in a neighborhood full of vagrants. I guess he really liked Cortech products, too.
Again, while I don't have the magnetic version, I'd suspect that the magnets would hold very tight and it would take a lot more than just a big bump to shake it loose. If something caused the bag to come off while riding, you probably have a bigger problem on your hands. The real issue with magnetic tank bags, though, is that the magnets will attract tiny bits of metal and flakes of magnetic rock that will then scratch up your tank. You don't want to learn this the hard way.
A forum community dedicated to Kawasaki Versys motorcycle owners and enthusiasts. Come join the discussion about performance, touring, modifications, classifieds, troubleshooting, adjustments, reviews, maintenance, and more!