This is a Dynalite #0703 Flashtube. It comes mounted in its own reflector, and installs easily in your RH1050 or 1015 flash head. Most current, professional flash heads and monolights are equipped with user replaceable flashtubes that may simply be plugged into, and unplugged from their sockets. With proper handling, these flashtubes may last for tens of thousands of flashes under normal use.