See usage instructions on the topknot page
Latex Bands & Elastic Topknot Bands For Dog Bows, Dog Grooming and Pet owners.

The following sizes are recommended, however this is only a recommendation. I don't know your dog.
3/16" - Show dogs - wraps once
1/4" - Show dogs, Pets with moderate hair - wraps once maybe twice
5/16" - Pets with thick hair - wraps twice maybe three times
3/8" - Pets with long, extra thick hair - wraps 3 times - great if you have a hard time using bands
5/8" - All Dogs - wraps 4 times - great if you have a hard time using bands
3/8" xtra hvy - for making dog bows, xtra thick topknots, Show dog wraps
Lightweight - puppies, dogs with fine hair
Latex - most commonly used, suitable for all hair, suitable for bows
Non Latex - slightly stretchier, suitable for all hair, not suitable for bows

100 bands are $2.00
300 are $4.80
500 are $6.00
1000 are $10.00
2500 are $19.00
5000 are $33.00
10,000 are $60.00
These other sizes available by special order in packs of 5000 or more
1/8" light, med, hvy in non latex, neon, amber
3/16" light, hvy in non latex, neon, amber
1/4" light neon, non latex
5/16 light amber, neon
3/8" light non latex, neon, amber

These bands are perfect for dog groomers and pet owners.
Easy to use, won't break or matt with proper use. Please
match the size chart to your current bands. To Properly
measure, use a ruler to measure the inside dimension.
We have many people that purchase these for craft projects, however
these bands are for "putting up" or the making of topknots, and no claim
is made for other uses including making your own bows. Please be sure
as to size (see above), as once opened they cannot be returned. If you
Choose to purchase neon or non latex to make bows, use at your own risk.