A botanical basket can be used in a couple of configurations based on what you're distilling.
Most commonly it is placed before the condenser in a pot still configuration, this is a type of vapour infusion. This means that all of the ethanol coming from the boiler must pass through the basket before it gets condensed back into a liquid.
It could also be placed after a vertical dephlegmator /condenser to allow a certain ABV running through the botanical basket. This can be beneficial as some alcohol percentages can diffuse different aromatics.

This is a Slightly tapered 3" Tri-Clover Botanical Basket made from 304 Stainless Steel designed to be used in a KL36962 - PolyPhoenix - 3 Inch TC Tee or KL36979 - PolyPhoenix - 3 Inch TC Straight Extension depending on your setup wants and needs.

Dimensions:
135mm Tall 
60mm Wide Base
Fits internally in a 3" TC without disrupting the 3 Inch TC Beaded Seal

Internal Volume:
Approx 400mL