This is a great way to introduce basic human proportions to middle school students. I was gifted a whole bunch of those wooden mannequins. I've also seen them at IKEA as well as some Dollaramas.
Grade 4 - 6 students had alot of fun putting the mannequins in different poses then drawing them from observation. I now keep them in a box in the Art room for students to use when they have free time. they really like using them.