The Trend-350 is a proprietary end terminal developed by Trinity Highway.
From the manufacturer's website:
The TREND® 350 Tangent End Terminal is a single-sided, energy absorbing steel post terminal. It is tested to NCHRP Report 350 Test Level 3 as a redirective, gating end treatment.
The system can be used at the end of W-beam guardrail between 27 ¾” to 31″ assembly heights. While the TREND® 350 Tangent is primarily used with single-sided W-beam barriers, special transitions may allow for use with other barriers.