The Ultimate Flue Outlet when originally introduced in 1995, was the first gas chimney cowl in the UK to pass the vigorous requirements of BS7 15:1993(200mm). Its ever increasing market share is testimony to its extensive benefits, advantages and superior antidowndraught qualities over other cowls. The U.F.O MKII cowl incorporates four adjustable upstands that address the need for a greater exhaust area demanded by the use of solid fuels. The compact nature of the U.F.O MKII means it can be used on several pots on the same stack without modification, something some other cowls cannot achieve. Fully assembled including factory fitted birdguard ready for use on gas systems. Simple adjustment of the four upstands makes UFO ready for use on solid fuel. Designed to fit flues and pots between 150mm and 240mm (6" - 9.5") internal diameter. Tested and certificated to BS715:1993, BSEN1856-1 2003 and meets requirements of BSEN1443:2003. Withstands temperatures up to 200C Suitable for use on gas systems to BS5871:2005 including Radiant Gas fires, coal and log effect gas fires, vertical flues, gas boilers etc. Performance tested for use on oil appliances - OFTEC. Better rain and bird protection than many other cowls. Please note: when the UFO MKII is used on a solid fuel system, the gas birdguard must be removed. Chimney is not supplied, this item is stainless steel.