NEW YORK ( TheStreet) -- Shengkai Innovations (Nasdaq: VALV) has been upgraded by TheStreet Ratings from sell to hold. The company's strengths can be seen in multiple areas, such as its robust revenue growth, largely solid financial position with reasonable debt levels by most measures and expanding profit margins. However, as a counter to these strengths, we also find weaknesses including weak operating cash flow and a generally disappointing performance in the stock itself. Shengkai Innovations, Inc., through its subsidiaries, designs, manufactures, and sells ceramic valves; and manufactures and sells ceramic materials. It offers ceramics gate valves, ball valves, back valves, adjustable valves, cut-off valves, and special valves. Shengkai Innovations has a market cap of $142.9 million and is part of the services sector and wholesale industry. Shares are up 0.3% year to date as of the close of trading on Friday.