The ornamental design for a double balldownspoutjoint, as shown and described.
FIG. 1 is a bottom perspective view of our new design for a double ball downspout;
FIG. 2 is a front elevation view for our new design for a double ball downspout, wherein a rear elevation view is identical;
FIG. 3 is a left side elevation view of our new design for a double ball downspout, wherein a right side elevation view is identical;
FIG. 4 is a bottom plan view of our new design for a double ball downspout;
FIG. 5 is a top plan view of our new design for a double ball downspout;
FIG. 6 is a front perspective view of our new design for a double ball downspout in a partially articulated position;
FIG. 7 is a front perspective view of our new design for a double ball downspout in a zigzag position;
FIG. 8 is a left side elevation view of our new design for a double ball downspout in a fully articulated position; and,
FIG. 9 is front perspective view of our new design for a double ball downspout shown in use in the upper downspout segment.
The broken lines indicating use on a house are for purposes of illustrating a use for our new design and form no part of the claimed design. The broken line showing of the interior of the double ball downspout joint is included for the purpose of illustrating portions of the article and forms no part of the claimed design.