It's in addition to previous message. I confused ETK description. It says "Water hose(shutoff valve > heat exchanger)" So, it is basically peace of water pipe? What is this plastic screw-like on top? Thanks! -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.308 / Virus Database: 266.10.4 - Release Date: 4/27/2005