How it's made. Two printed parts in PLA, no supports: the body (walls, floor and gable ends in one piece, the name inlaid flush in the front) and the roof, printed ridge-down. Two keys under the roof drop inside the gable walls so wind can't shift it, and it lifts straight off to clean out last year's nest. Two keyholes on the back hang it on a pair of screws in a post, fence or tree. Hole sizes follow the nest-box guides — 29 mm for wrens and chickadees, 32 mm for titmice and nuthatches, 38 mm for bluebirds — and there's no perch on purpose: perches only help predators. Hang it in the shade; PLA keeps its shape best out of direct summer sun.