Honeywell TK Series Combo Boiler Trim kits are a quick and convenient way to purchase the key "boiler trim" used by installers when performing a boiler change out. All Combo Trim Kits with SuperVent include expansion tank and SuperVent high performance air eliminator; selected models also include FM911 combination boiler fill valve / backflow preventter and/or service check valves for in-line servicing of the expansion tank. This kit includes item numbers TK300-30, PV125S, SCV-050 and FM911.