Micro fishing tippet connectors allow you to quickly and easily attach a snelled tanago hook to your main line. No knots or loop to loops are required. I learned about them from the Micro Fishing Kit because it uses one. It makes rigging or re-rigging much easier than messing around trying to tie a knot in a 1 lb test line (even if it is red so you can see it).
The connector has an eye to tie it to your main line. The other end of the connector is essentially a hook with no gape. You slide the snell from the tanago hook into it, wrap it around once and slide it in again. (There is an illustration showing how on the back of the package.)
It doesn't slip. I don't know if it significantly weakens the tippet, but the snelling on the tanago hooks is about 1 lb test to begin with, so great strength is not its primary attribute.
Please note: the tippet connectors are specifically designed for use with snelled tanago hooks. If you use them to connect regular tippet to a tenkara line, it will not hold. I suspect the material used in the snell of the tanago hooks is softer and not nearly so slick.
Besides, as I have mentioned before, I think one should give the micros a fighting chance. If there is no possibility that anything you might hook could break your line, it takes a bit of the uncertainty and a lot of the heart-in-your-throat adrenaline out of the whole process.
Now you might snicker at the idea of heart-in-the-throat adrenaline while fishing for minnows, but when atenkley hooked an 11 or 12 inch channel cat while fishing for minnows, I will bet you his heart was in his throat! (And yes, he landed it with his 6'6" Soyokaze.)
Owner Microfishing Tippet Connectors - $4.50 (package of 10)