Cat5e splitters are not here to replace routers or switches, although they do split one connection into two connections.  It is able to make two signals through one cable by placing one adapter at one end and another at the other end.  

The splitter is typically used for phone or security systems in SoHo (Small office/Home office) networks.  This is allowed since phone and data transfers only use two of four twisted pairs, allowing the splitter to use the unused pairs to support the second connection.   

Internet access can also be shared, but it only supports one connection at a time since there is only one IP address.  The splitter supports two connections, but uses all four twisted pairs at a time to transfer the Internet connection. 

By purchasing this splitter you will be saving yourself money and time by not purchasing more cable to run through your walls or ceiling.  You will have to purchase two (2) splitters for the split to actually work. If you plan on adding just one extra connection in your SoHo, then this is a prefect fix for you.