A fitting in the form of the letter y with each branch usually fixed at 45 degrees (0.78539 radians) to the run. It has identical flanged ends.
NSN 5915-01-100-4105
NSN 6650-00-107-8509
NSN 5895-01-295-5366
NSN 5985-01-261-6756
NSN 6650-01-519-0399
NSN 6620-00-235-4938
NSN 6685-01-492-4491
NSN 5910-00-394-9524
NSN 7035-01-448-4740
NSN 5965-01-140-5555
NSN 6135-00-295-2614
NSN 6320-00-343-1798