Brush Mate Fluid has been specially formulated for use in the Brush Mate Trade 20.  Once the fluid is fixed into the Trade 20, the wick is placed into the bottle and fluid is drawn to the vapouriser panel, which in turn emits the vapour that prevents brushes from hardening. 

The Brush Mate Fluid is for use in the Trade 20.  Typically a Trade 20 will consume about 2 - 3 ml.  of Brush Mate Fluid per day, so you may expect to replace the bottle of Brush Mate Fluid every 3 - 4 months.  However in some circumstances (e.g.  if you store your Trade 20 in a van where there are large temperature fluctuations) consumption can be greater.