Refusing L.A.'s beck and call, sisters Chelsea and Justine Brown prefer to work out of their Inland Empire hometown of Riverside, where they've been cutting their teeth as the garage pop duo Summer Twins since 2008.

Aligning themselves early on with another California empire, they signed with the prolific and ubiquitous Burger Records, delivering a 2012 self-titled debut that walked to a similar retro beat as bands like Vivian Girls and La Sera, taking cues from '50s and '60s girl groups, surf music, and garage rock.

They kept busy releasing a handful of EPs and smaller releases before pairing up with producer Chris Woodhouse (Thee Oh Sees, Ty Segall) in Sacramento to record their follow-up, 2015's Limbo.

While much of the music from Burger and its surrounding scene favors a loose, D.I.Y.

aesthetic, Summer Twins have continued to tighten up their sound, and Limbo is both leaner and more muscular than anything they've done before.

Opening with the snaky, noir ballad "Blinds," Chelsea (guitar, vocals) and Justine (drums, vocals) exude confidence and charm, delivering a slow dark groove ornamented with a lovely and effective string arrangement.

Their songs still come from the same well of vintage rock and pop, but the material has grown to fit their evolving personalities and styles.

Prior to this release, Chelsea handled the bulk of the songwriting duties, but on Limbo, Justine makes her debut with a pair of fine tracks ("Florence" and "Helpless") on which she plays every instrument.

There are plenty of other bands working in this surfy, garage-inspired territory, but Summer Twins have a very nice handle on it, and their beguiling voices take songs like the torchy "Our World" and the dreamy, playful closer "So Funny" to another level.

Underneath their guitar rock patina are some appealing and well-crafted pop songs more akin to She & Him than some of their fuzzier, lo-fi contemporaries.

Limbo is a strong sophomore effort from a talented young band.