SMC KQ2R07-11 Plug-In Reducer, 1/4 x 3/8" Tube, Tube. More details: Plug-In Reducer, Basic Material Plastic, Body Material Polybutylene, Connection Type Tube, Tube Size 1/4 In., Stem OD 3/8 In., Max. Pressure 145 psi, Color White/Gray, Temp. Range 23 Degrees to 140 Degrees F