New Avago Technologies (HP/Agilent) RF Schottky Barrier Diode, Part Number: HSMS-2828-TR1G in SOT-143 Package, in Bridge-Quad Configuration. RoHS.

It's low capactance, low reverse leakage current makes it ideal for Mixing, Detecting, Switching, Sampling, Signal Clampling and Wave Shapping. Device Marking: C8J.

General Spec:

Minimum Break-Down Voltage: 15V
Maximum Forward Voltage: 0.34V
Maximum Reserve Capactance: <1.0pF
Configuration: in Bridge Quad (picture #8 from data sheet)