View umt3904 datasheet:

UMT3904 / SST3904 / MMST3904 / 2N3904 Transistors NPN General Purpose Transistor UMT3904 / SST3904 / MMST3904 / 2N3904 Features External dimensions (Units : mm) 1) BVCEO > 40V (IC = 1mA) 2.0±0.2 1.3±0.1 0.9±0.1 UMT3904 2) Complements the UMT3906 / SST3906 / MMST3906 0.65 0.65 0.7±0.1 0.2 (1) (2) / 2N3906. 0~0.1 (1) Emitter (3) ROHM : UMT3 (2) Base EIAJ : SC-70 0.3 +0.1 0.15±0.05 -0 All terminals have same dimensions (3) Collector 2.9±0.2 +0.2 0.95 SST3904 1.9±0.2 -0.1 Package, marking and packaging specifications 0.45±0.1 0.95 0.95 (1) (2) 0~0.1 Part No. UMT3904 SST3904 MMST3904 2N3904 0.2Min. Packaging type UMT3 SST3 SMT3 TO-92 (3) (1) Emitter Marking R1A R1A R1A - +0.1 (2) Base 0.15 +0.1 -0.06 ROHM : SST3 0.4 -0.05 Code T106 T116 T146 T9