About 450 small-business operators across Japan filed a raft of lawsuits Tuesday against the failed Tokyo-based retailer Idic Co. and eight consumer credit companies, claiming they were cheated into buying an expensive electricity-saving device that made no dent in their power bills.

The device -- known under the brand name Sho-den-o, or King of Electricity Saving -- was sold at prices ranging from several thousand yen to just under 2 million yen apiece.

The plaintiffs, most of them owners of restaurants and general merchandise stores, are seeking a combined 160 million yen in damages for money they paid to consumer credit companies plus a debt waiver on 280 million yen in pending installment payments.