ZZM 2-in-1 luggage strap for carry-on bags

The straps are hook-and-loop and adjust to most handlebars; the wagon console is the one made for a wagon rail rather than a bar. The product pages name the models the brand lists, and if yours is not on that list, measure the bar before you order.

It is an elastic strap that holds a second bag onto your carry-on handle, so it travels with the bag rather than being checked. Airlines count bags, not straps; the strap does not change your allowance.