Add-A-Tee Adapter,Lead-Free Splitting Water Supply Fitting 3/8" Compression Inlet x 3/8" Outlet x 1/4" Outlet,Brass 3 Way Adapter Or Tee Connector With Sealing Gasket(1 PCS) - Amazon.com
1/2" Female Compression x 3/8" Male Compression X 3/8" Male Compression Repair Add a Tee - Noel's Plumbing Supply
SharkBite 3/8-in Od Female Compression x 3/8-in; 1/4-in Od Compression Brass Add-a-tee in the Shut-Off Valves department at Lowes.com
Under Armour - Women's UA Tactical HeatGear® Compression T
Ace Add A Tee 3/8 in. Female Compression Swivel X 3/8 in. D Male Compression Brass Adapter - Ace Hardware