Cisco WS-C3750X 48T-S 48 Port Gigabit Switch & 2x 350W Power

WS-C3750X-48T-S

Cisco Catalyst 3750-X Series Switch

Stackable 48 10/100/1000 Ethernet portsFour optional uplink network modules with GE or 10GE portsDual redundant, modular power supplies and fansMedia Access Control Security (MACsec) hardware-based encryptionFlexible NetFlow and switch-to-switch hardware encryption with the Service Module uplinkUSB Type-A and Type-B ports for storage and console respectively and an out-of-band Ethernet management portStackWise PlusCisco StackPower^TM technology: An innovative feature and industry first for sharing power among stack membersCisco StackWise Plus technology for ease of use and resiliency with 64 Gbps of throughputInvestment protection with backward compatibility with all other models of Cisco Catalyst 3750 Series Switches

Cisco Catalyst 3750-X Series Switches support 4 optional network modules for uplink ports below:
The default switch configuration doesn't include the uplink module; 
When purchasing switch, customers have flexibility to choose any group of network modules described below:

                                                                                              Figure 2

Dual Redundant Modular Power Supplies

Cisco Catalyst 3750-X Series and 3560-X Series Switches support dual redundant power supplies (Figure 2);
One power supply is shipped with the switch by default;
Other power supply/suppliers can be purchased when ordering the switch or next time according to your needs.
If only one power supply is installed, it should always be in the power supply bay 1.

Table below shows the different power supplies available in these switches and available PoE power.

Power Supply Models