Rab Interval Long Sleeve Zip Tee

This is a lightweight, versatile baselayer that offers good sun protection and will stand up to days of nonstop use and abuse on the trail. If you like the colors, it is worth considering.

I was looking for a shirt to wear for a 12-day trek at Philmont Scout Ranch. Since the conditions are sunny at high altitude, not the greatest for my fair skin and family history of skin cancer, I was looking for something with a good SPF rating, light enough to handle the heat, and an anti-bacterial treatment that would allow me to wear it for 10 or 11 days straight. 

I looked at several Merino-based products, but none of the makers would say anything about sun protection. I have an Orvis DriRelease shirt, but despite the claims of anti-smell treatment, my shirt stinks after a few days' wear and doesn't smell that fresh after laundering, either. In the end, the Rab Interval was the only one I found at a reasonable price ($65 MSRP) that ticked all the boxes. 

The only thing I'd change about this shirt is the colors. This is a great shirt for summer wear, but the colors are on the dark side, absorbing the sun's energy. It would be great if they could offer a light gray or blue that wouldn't look dirty on the trail but also reflect heat better.

Fit:  I am about 5'6" and 130#, and a Rab Small fits me perfectly in this shirt. I have a few of their MeCo baselayers (L/S and S/S) and made the mistake of buying them in Medium, which is a bit loose and too long in the sleeves for the L/S shirt. The company says the Interval is their regular fit, and I found it neither snug nor baggy.

Adjustability:  There is a generous half-zip that goes down past my sternum for a lot of venting when the weather got hot or on uphill climbs. The sleeves push up to the elbows easily for further venting. (My Sierra Designs Pack Polo L/S is too tight in a Small to push up my arms, one reason why I didn't use it.)

Breathability:  This shirt wicked perspiration away quickly, keeping me dry and comfortable unless I was really at maximum effort climbing a steep trail.

Abrasion/Durability:  The shirt looks almost new after a tough 70 miles of backpacking. There are a few tiny holes around the waist on the front, but those may have come from a trail maintenance project where I was carrying 30-50# rocks in a bear hug. Minimal pilling around the cuffs and forearm seams.

Function:  This shirt did everything it said it would. I didn't get sunburned, I stayed cool and comfortable, and with a few rinses along the trail, I was able to wear this for 10 days in a row without stinking up the place.

Conditions:  I wore this mid-summer in northern New Mexico, with daytime highs in the upper-80s or low 90s. I will probably use this as a baselayer for my winter biking commute under a cycling jacket, and if there is anything relevant to report, I'll update the review.