Metal Earth kits are amazingly detailed etched metal models that are fun and satisfying to assemble. Each model starts out as 4 inch square metal sheets and you simply pop out the pieces using wire cutters and follow the included directions to assemble your model. This kit from the hit sci-fi series Doctor Who lets you build K-9, the Doctor's lovable robotic canine companion. Difficulty level: Easy. No glue or solder needed.