We have a very limited supply of new colors in size 16 long prongs. The cap prongs are 6.2mm in length--same as the size 20 long prongs--and are suitable for thicker fabrics or more layers.
New colors are:
B44 Apple Green
B47 Neon Pink
B56 Bright Purple
These colors will not be restocked once they sell out so get them while you can. You'll find them on the Basic Snaps product page: http://www.kamsnaps.com/Basic-Snaps-p111.html