Wick Sustainers (also referred to as Metal Tabs) are required to hold your wick in place at the bottom of the heat resistant container and stops the wick from simply floating to the surface of the candle when you pour in the molten wax. To use, crimp the wick and place into the hole in the sustainer - if you find this difficult, try using small plyers. You can use a small amount of glue placed into the hole beforehand and then allow it to set with the wick in place.
When placing the sustainer on the bottom of the container, if you have some Blu Tac handy, a little tip is to place a very small amount under the sustainer and stick it to the bottom of the container. Alternatively you can use a double-sided sticky paper spot/tab available from all good stationery stores and some food retail outlets.
This sustainer is 20mm in width and is suitable for relatively large sized containers. If using a small to medium sized container select the 15mm option. The height of the sustainer can be selected from the drop down box above. If you are not used to using sustainers, then the larger of the two (6mm) can make it slightly easier to hold the wick in place.