A young San Francisco entrepreneur has been issued U.S. Patent No. 4,033,358 for a unique product that has become the talk of the roll-your-own set.

The product is called "Instaroach," and if that's not enough, on the package is a drawing of a red-eyed roach, in the classic "laid-back" position, puffing away at what could be described as a joint.

"Randy's Instaroach," the package says, "Wired rolling papers - Made in San Francisco."

Inside are twelve leaves of rolling paper with an added bonus. Each paper has a built-in wire. When the smoker has smoked half of his or her cigarette, the wire can be held in such a way to allow the smoker to puff down to the very end - without the aid of a "roach clip," the popular device now used for such purposes.

The paper is the brainstorm of 35-year-old Duane Harrington, who earned a doctorate in chemistry at the University of California at Berkeley.

Harrington created both the product and the machine to make it last May.

With a staff of five, Harrington began production of the papers in a co-operative warehouse near the Fillmore District of San Francisco.

In each of the last five months, since the patent was issued and the promotion of Instaroach among distributors begun nationwide, sales have doubled.

Instaroach International now does about $55,000 a month in sales, according to office manager Jim Neubert, a 32-year-old certified public accountant who supervises the growing staff which now numbers 24.

Remarkably, Instaroach has done no advertising, although there are discussions about future ads in such magazines as "High Times," - a magazine devoted to the study of various drugs and a clearinghouse for advertisers in the drug paraphernalia business.

But word-of-mouth advertising alone has worked successfully for Instaroach.

"We get letters all the time," Neubert said. "A lot of people just write to tell us that they think the papers are a great idea. One person told us it was the greatest thing since filters.

"One elderly couple wrote to us to say that their son gave them the papers, already rolled, and the experience turned their ordinary two-day week-end into a "four-day-holiday," said Neubert.