Rated Cat5, it supports 100 MHz Ethernet links.
Mounting and PCB Fit
The tab direction is down, which means the locking tab on the mating RJ45 plug faces the PCB — check your plug's cable exit orientation before layout. Through-hole solder termination gives a mechanical anchor that handles cable strain better than SMT alone. The jack can also be panel-mounted for front-panel Ethernet ports, using the EMI fingers to bridge the jack shield to the panel ground.
Shielding and Signal Integrity for Cat5
The shielded shell with EMI fingers is the feature that makes this jack Cat5-capable. Unshielded modular jacks lack the ground return path for high-frequency common-mode noise.