Hair Extension Tape Tabs
If you've done any sort of hair extensions with tape I'm sure you know what these are. They are little tape tabs designed to fit perfectly on hair extensions. You can get them in a bunch of different tapes with different hold times.
I personally prefer a new product called Duo-Pro. It's the only tape I've heard of that is developed specifically for Hair Extensions. It has great hold times and cleanup is super easy. I seriously recommend it to everyone I know.
I found this video review that talks all about Duo-Pro.
After Duo-Pro I recommend No-Shine and ProFlex II.
I like No-Shine a bit more, although it is harder to apply.
I just found out that if you are a stylist or a business owner you can buy Hair Extension Tape Tabs direct from the manufacturer at HairExtensionTape.com. You'll save a bunch of money and I always like to get products directly from the source, when possible. You can also buy solvents, clips, conditioners, etc. It's such a good resource.
If you have to pay retail I would buy from Amazon. They seem to have the best prices with shipping. Good luck!