Gakken's "Mechamo Series" of kits are more complex than kits intended for younger hobbyists (though of course with adult supervision, there's no reason a bright youngster can't put them together!). This metal centipede (check out all them legs!) comes with everything you'll need to build it; requires 6 AA batteries, sold separately. Download the parts list and the English instructions (both are PDF files. If you don't have Adobe Reader, download it for free!