(FORTUNE Magazine) – The beer cooler, that mainstay of American summers, seemed endangered when two small companies, Superior Marketing Research Corp. of Salt Lake City and Laser Arms of New York City, said they would soon begin test-marketing self- chilling cans (FORTUNE, May 12). But the Securities and Exchange Commission temporarily halted trading in Laser Arms shares April 21, charging that the company has no rights or patents to such a can and that its balance sheet in the interim report to stockholders is ''entirely fictitious.'' Though Laser Arms officials have not returned phone calls, Superior says development of its can is coming along nicely.