Fits T500 boiler - a distilling column condenser for reflux distilling made from stainless steel.

Stainless steel is the most durable metal in distilling and is much harder than copper.
By buying the stainless steel condenser (instead of the copper one) you trade the positive effects of copper (cleaner flavour of your distillate) for durability.
However, you can fill the column with copper mesh to get the copper effect.