This is one of the more unique Mosque in the country for it's design. Visitors must adhere to the rules, you have to dress decently, no shorts or anything of that sort to remain respectful to the local community there. There are the usual facilities for ablution (wudhu), and toilet. Actual prayer area is not so big, but I'd say enough to fit 50-70 people (or more). I'd say it's a must go if you're in Kuala Kangsar.