Does WS-C2960S-24TS-L / 4 SFP Ports For A Switch?

[LNort]

I have got a requirement where a 24 port switch should have 4 SFPs and all 4 should be used at a time. I also search the internet and find both http://www.router-switch.com/ws-c2960s-24ts-l-p-1516.html Cisco Catalyst WS-C2960S-24TS-L and http://www.router-switch.com/ws-c2960s-24ts-s-p-1518.html WS-C2960S-24TS-S seem to be avalible.I don't know the difference between them ? Which one should i buy ?