I am making a necklace with a fair amount of beads attached to chain.
The buyer would like to be able to put charms on the necklace on
occasion and remove them on occasion.  These are alphabet charms and
they will be put on a double link charm bracelet style chain (though
it will be a necklace) so they will need to be very small clasps so
the letters will lay as flat as possible.  Here is a link to the
bracelet version.  http://www.lemonpocket.com/bracelet.jpg

I thought I heard of something called a CHO clasp or C H O clasp, but
I have no idea what it is.

Thanks in advance for your help.

Libbi