Membrane Electrode Assembly (MEA) includes the membrane, catalyst layers, and gas diffusion layers (GDLs). The MEAs are available in 3 and 5-layer configurations.
A 3-layer MEA is also referred as Catalyst Coated Membrane (CCM) where each side of membrane is coated with catalyst layer over the electroactive area. The CCM needs to be assembled with two GDLs when making a fuel cell.
 
A 5-layer MEA is assembled together by means of a lamination the membrane, catalyst layers, and gas diffusion layers all together.

Gasket

One of the important parameters in a cell build is the thickness of the gaskets. The gasket thickness determines how much the flow fields are allowed to pinch into the electrode. For a good contact (i.e., low contact resistance), it is essential that the ribs of the flow fields bite into the electrode providing good contact.
Membrane Electrode Electrode (MEA)
​Catalyst Coated Membrane (CCM) 
Gasket