Clothing retailer Forever 21 Inc. isn’t taking the inroads made by “fast fashion” rival H & M; Hennes & Mauritz AB lightly.

With the Swedish company opening three stores in its Los Angeles County back yard over the past year, L.A.-based Forever 21 is launching a string of outlets geared to fashion-conscious 20- to 30-year-olds, called Heritage 1981.

Both of the companies specialize in inexpensive clothing, which is quickly manufactured and inspired by some would say knocked off the styles created by major designers

Forever 21 has opened concept Heritage stores in Mission Viejo and San Jose and a Beverly Center location is in the works.

“We are thrilled to open a new concept store that expands our merchandise range. We will use our consumer friendly strategies of new fashion and everyday deliveries at a great value,” said Forever 21 Senior Vice President Larry Meyer. Four more locations are planned, in Bloomington, Minn., Chicago, Philadelphia and Woodbridge, N.J.

While Forever 21 stores are sprawling, packed with merchandise and designed to appeal to young ladies and their mothers, the new stores have a tighter focus and higher-quality clothing.

Heritage clothing, priced between $25 and $50, is made of natural fibers, in contrast to Forever 21’s clothes, which are usually priced in the $15 range. Half of the Heritage clothes are men’s; all of the Forever 21 items are for women.

Heritage clothes are classically inspired, woven pieces with colorful prints and plaids, knits and carefully faded denim. Notably absent are career clothes and clubbing duds.

The atmosphere of Heritage stores also will contrast with the Forever 21 stores, with weathered doors, wood-framed windows, vintage artwork and hardwood floors. Forever 21 stores have standard white walls and white floors, and pop music is always humming.

Forever 21 grossed $925 million in 2005, and revenues are expected to top $1.1 billion this year.