Dressing for outdoor spring workouts can be tricky. It's usually too cold to start out sleeveless, but after 10 minutes or so, I start to overheat and want to shed a layer. But who wants to run with a jacket flapping around her waist? Not me. Happily, I may have found the solution with the versatile new Merrell Longmont top.

Check it out: This cute racerback tank comes with a matching shrug. Worn together, they look like your run-of-the-mill long-sleeve workout top. But once you heat up and need to shed a layer, voilà! The shrug comes off, you wrap it around your waist, and you're good to go. No flapping, no bulk—and most importantly, no mid-workout meltdown. Brilliant.

Other things to like about it: It wicks and breathes well, and it's actually long enough to cover the waistband of my shorts (I'm amazed by how many long tops don't). Plus, it has thumb loops (love those!), a hidden zippered pocket in the back, and an MP3 pocket on the sleeve.

It's not perfect, of course. When I moved my arms, the skin around my underarms kept peeking out, spoiling the single-top illusion—and giving me a bit of a chill. Plus, the built-in shelf bra isn't up to supporting anything more intense than a walk—at least, not for my D-sized girls. Luckily, I found that it works just fine with a more substantial bra underneath.

Also, with the exception of a single silver strip on the back of the tank, there's no reflectivity—something to consider if you work out, as I do, in the dark of the early morning (or in the evening).

Still, the style is so cool—and cooling—that I'm going to make this top a permanent part of my spring/fall workout wardrobe.

Product: Merrell Longmont top

Category: Apparel

Pros: The combination of tank and a removable shrug makes this a truly flexible top. It's cute, with fun extras, and it wicks and breathes well.

Cons: The shrug shifts when you move, and the top isn't very reflective. Also, larger-breasted women will need to wear a more supportive bra underneath.

Cost: $79 at Merrell.com

Extra tip: Wear the tank alone during yoga class, then add the shrug afterward as a cover-up.