String Wound Sediment Filter. Fits Hydrotech HTF Series Reverse Osmosis systems. All 4 stage systems require this as the first filter. On the 3 stage systems with a CTA membrane this is the first filter. On 3 stage systems with TFC membrane the 41400009 is the correct first filter.
Hydrotech sediment filters are made in China. We send a Big Brand Water Filter brand sediment filter that is OEM made in USA. This is the original equipment filter that the system was designed with many years ago.