There are other thru axle adapters on the market, there have been for years. However, there are none that let you lock your beloved ride to your roof without some janky cable and padlock style contraption. The RockyMounts Drive Shaft answers the call with a clean, easy to use design that will have mountain bikers dancing and thieves running away, confused. The other beauty of the Drive Shaft is that it, unlike the other adapters that are available, accepts both 15mm and 20mm thru axles. You'll need to keep the plastic reducer shims handy to accommodate your 15mm axle, but it's much more convenient than swapping adapters. And it's much, much more convenient than replacing your stolen bike.