In my opinion this is a handy multi-pupose mount - Garmin Backpack Tether

This mount can be used for more than a back-pack tether which I'm sure it would be perfect for. Because the Garmin attachment clip that mounts to the back of the Dakota 20 has velcro connecting it to the mounting base, which also has velcro straps to mount to what ever you want to attach it to, you can use this mount for many things. You can reorient the mounting clip 90 degrees to the mounting base and use it for handle bar mount or extend the velcro straps and mount it to a roll bar. The uses are endless, you can even use it as intended and mount it to your back-pack. The The lanyard is also about the same diameter as 550 paracord so if it is not long enough for you, just make a longer one in your choice of color out of paracord.