We have our F0005 plug-in flash tube,custom manufactured specifically for our M300,M500,and M600 Monolights. The tube is enclosed in a thick,vented glass envelope,a tough ceramic base,and the three prongs that plug securely into the Novatron Monolight instruments. The tube is color balanced to 5500 degrees Kelvin and rated at 700 watt/seconds. The Monolights' fan-cooling allows it to operate at maximum efficiency. This plug-in style is an instant remedy,if the flash tube is ever broken,all at the user's simple installation.