craftgrrl | *grumbles* jewelry makers please?

So OCCASIONALLY when I'm placing large bead and finding orders I miss a letter or two
and receive an unwanted surprise..I somehow ordered 100 End caps

I have NO idea what these do! I'm self taught, and I missed this page...

http://www.firemountaingems.com/details.asp?PN=WE2201FN&GEN1=end%20caps&GEN2=2

Is what I ordered...the hole is tiny, like a beading wire is about the most you could get through it, but the cap itself is LARGE.. like 1/3rd inch wide?? so I don't get it...not at all...if I thread anything through it it's going to end up looking like a bell..
any ideas on how these work? I'm sure i'm missing a very simple step..