Double Slideways, 6 piece coordinate motion puzzle, designed by Ray Stanton and made by Eric Fuller in 2014. Very nice condition, fit is a little loose, as it originally was. Pictures show it fully assembled, and partially disassembled; I didn't want to take it all the way apart for the photo because it isn't easy to reassemble!
Postage is $15.70 for the US, and $28.55 for international.