QCPN Series is a 316 Stainless Steel Non-Valved through-type Coupler with a Compression connection to a Plug-in Stem. The OD sizes are 1/4" and 3/8". The temperature range is 0º F to 150º F. In fact, the maximum working pressure is 150 psi. This coupler works well with Polyethylene, Nylon, Polypropylene, or Vinyl tubing. This coupler is also available in Chrome-Plated Brass. Also the nuts will rotate around the sleeve to prevent twisting the plastic tubing.