Casual footwear startup Allbirds has secured a $7.25 million Series A funding round.

Venture capital firm Maveron is the lead investor in the round. Also participating in the round are seed investors Lerer Hippeau, Peterson Partners, Great Oaks VC, Red Sea Ventures and Slow Ventures. The startup in November closed on a $2.8 million seed round.

Allbirds was founded in 2014 by Joey Zwillinger and former professional soccer player Tim Brown. The first style by the footwear firm was the Wool Runner, a sneaker made from a superfine New Zealand merino wool fabrication for the top. Leather is not used in any of the sneaker’s components, whether the top, insole or outsole, which helps to reduce the carbon footprint. The original style retails for $95 a pair, and is available for both men and women.

According to Brown, Maveron’s Dan Levitan is joining the company’s board. About 90 percent of its customers are in the U.S., and the balance are from New Zealand, the founders’ hometown.

Brown said in early 2017, the company plans to introduce a new style in its casual footwear line. Also coming up for early next year is the ability to remove the insole to free up space in the shoe so users can insert an orthotic if needed. The start-up has a pop-up that just opened inside a Shinola store in San Francisco.