For example: Which (apparently keyboard) instrument is this?
In the help it mentions that instrument identification questions are off-topic. I can't think of a good reason for this - other off-topic specifications are usually something to do with the question being likely to go out-of-date quickly.
ID questions can be useless if they're vague, but can be pretty interesting if they're well specified. Some other sites allow ID questions, but have strong requirements (e.g. EarthScience.SE).