If you're planning on making candles, you will absolutely need these candle wicks.

Wicks have different sizes in diameter that are rated in number of strands. You need to choose the right size for the candle you are making. The bigger the candle in diameter, the more strands it needs.

If you choose a wick too small for the candle, it can make the flame go out or will not burn properly causing it to have a big tunnel inside the candle with a big part of the exterior of the candle that is not melting.

If you choose a wick too big, the flame will be much bigger and can cause a lot of smoke and the candle will melt much more faster.

The number of strands needed for one candle to burn properly can also vary from material you're using to make the candle (wax, paraffin, etc.), the fragrance, the form of the candle, color, etc.

Its important to find the right size for the type of candle you're making. Very often, its a game of try and error.