They appeared to be of good quality. The only problem I had was that the valve cover gasket was too loose in the valve cover groove so parts of the gasket fell out of the groove when I turned the valve cover over to install it. I ended up having to use a tiny bit of silicone gasket material to hold the gasket in place and quickly flip the lid over before the gasket came out. Once the gasket is in place and the cap is properly screwed on, the gasket expands and fills the groove. The problem seems to be related to the slippery nature of the material. I don't remember original Mitsubishi gaskets having problems like this, but they cost three times as much now.