A "keeper" is a simple device for securing a cord to something else (sometimes another cord or even itself). They are handy for sub-dividing garland wand looplets or adjusting the size of a tri-string loop or for binding the top and bottom strings of a modular tri-string loop.
Many different devices can be used as keepers: small hair clips and scrunchies, cord locks, twist ties, etc. A handy lightweight keeper can be made from a bead and a rubber band or small hair elastic as shown below.
Rubber bands are great for keepers that you tend to leave on the loop. I often put a keeper on either end of the top-string of large loops so that I can make the effective loop size smaller. And for garlands with large looplets, I will put one or two on per looplet. I slide them into place to subdivide the looplet if I want smaller looplets and slide them out of the way to restore the original size.
Hair elastics, because they are thicker, are easier to put on and take off in the field. When I make a keeper with hair elastic, I use a drop or two of super glue on the lark's head knot to keep it from coming undone.
Hair Clips[]
Mini-hairclips like those shown below make great keepers and can be used to quickly turn a tristring lop into a garland wand or to reduce the effective size of a loop. The latter can be useful if you have a loop that is too large for current conditions. They can be found at large supermarkets, drugstores, convenience stores and beauty supply shops. I keep a couple of them clipped to the dowels that I use as tristring handles. Scrunchies can also be useful.
Homemade Keepers[]
Cord Locks[]
Cord locks are used by some bubblers especially with large loops. They can be useful for reducing the size of a large tri-string in the field.