The part in the bottom red circle is a brass female 1/8" T. The piece above it is a 1/8" male to 1/4" female adapter. The adapter is required to connect the relief valve (1/4") to everything else (1/8"). I can't find any of the female T's at AndyMark, but here is a link to the same product from AutomationDirect:
http://www.automationdirect.com/adc/...e_Tee/BFFT-18N
The adapter is available on AndyMark:
http://www.andymark.com/product-p/am-2381.htm
and also at AutomationDirect:
http://www.automationdirect.com/adc/.../BFMFR-14N-18N
My team used our $20 AutomationDirect voucher to buy a whole bunch of these brass fittings, and I think it was money well spent.