K-Swiss Inc. is being purchased by South Korean retail conglomerate E. Land World Ltd. for $170 million in a cash-for-stock deal, the companies announced Thursday. Investors are being offered $4.75 for every share they own in the Westlake Village maker of casual footwear. The price is a 49 percent premium over K-Swiss’ closing price of $3.19 Wednesday on the Nasdaq. K-Swiss directors unanimously approved the deal Wednesday. The company has been struggling with falling sales. Its share has fallen nearly 80 percent over the last five years. The sale is expected to take close in the second quarter of the year after receiving approval by stockholders. Chairman and Chief Executive Steven Nichols controls nearly 70 percent of shares. The company got its start in 1966, when its “Classic” shoe debuted at the Wimbledon tennis tournament. It was the first leather tennis shoe produced. Shares of K-Swiss were up $1.52, or about 47 percent, to $4.71 in midday trading on the Nasdaq.