Cylinder   Parker (MFGR # 02.00 C4MAU18A 8.000).  
2” Bore, 8” stroke, 5/8“ Rod    3/8” NPT ports
I purchased this Cylinder on eBay.  If you want to purchase this specific Cylinder, look for distributors that sell Parker Cylinders.
4-Way Valve  Norgren (MFG # MN01CGA73A000).  
Purchased from Allied Electronics.
Alignment Coupler    # EAC-500F.
Available from E & E Special Products.
These are also available from other Industry Suppliers (Google for “Alignment Couplers”).
Roller Valve  Norgren (MFGR # 03061122).   
Purchased from MSC.
Air Gate   Norgren (MFGR # 03061122).  
Purchased from MSC.
Note: This air valve is the same (physical valve) as that used for the Roller Valve.  It’s function and plumbing configuration however, is completely different.
Check Valve  Deltrol (Part # EDC30B).    
Purchased from Penn Aire.
Butterfly Valve 1    (Part # 9798K33).
Purchased from McMaster Carr.
Butterfly Valve 2    (Part # 9798K33).
Purchased from McMaster Carr.
Venting Valve    1/4” NPT Ball Valve.
Purchase from any hardware store.
Fittings (Nipples, elbows, tees, etc…).   
Purchase from any hardware store or industrial supplier.
Air input side…  Use non-ferrous metal (Brass or bronze).
Exhaust side…  Ferrous metal can be used.
Hose Connectors   
Purchase from any hardware store or industrial supplier.
Use non-ferrous.  Shop around, prices vary a lot.
Purchase from any hardware or auto parts store.
Flexibility is important.
Use 1/4” air hose for Roller Valve and Air Gate. 
Use 1/2" air hose for the Cylinder and exhaust. 
Air line from shop air source
Minimum of 3/8 ID for short runs. 
Be sure all connectors have at least 3/8 ID.
Muffler  Fabricated, filled with steel wool.
A small engine muffler may be used....  
    Purchased from any hardware store.

Hose Clamps  
Purchase stainless steel clamps from any hardware store.