The Welsh pibgorn belongs to the class of instruments known as reedpipes, ie. simple pipes powered by a single beating reed, without or with fingerholes to allow the playing of different notes. They form a subclass where a horn, usually cowhorn, is used as an amplifying bell, and these instruments are variously either simply mouthblown or part of a bagpipe. (Description comes from the http://www.pibydd.fsnet.co.uk/ web-site.)