These are the RCS doors located on the side of the service module. It will replace the current parts on the 1/32 Monogram Apollo spacecraft with higher details. In accurazing the SM you can choose to scatch build the new RCS doors as I did with 0.25 mm styren sheets (see http://spacemodels.nuxit.net/1-32%20CM/Service%20module/007.html
) or you can use these parts. In this case since the thickness of the first layer (0.25 mm) is too thin to be printed so you will need to cut the service module plastic skin much like I did for the lower radiators (see http://spacemodels.nuxit.net/1-32%20CM/Service%20module/009.html
These 4 parts RCS doors can be used if you do not intend to show the inside of the service module.
For further information about building the 1/32 Monogram CSM check my web site at http://spacemodels.nuxit.net/1-32%20CM/index.htm