In your inventory you might see SKUs that look like this
First off, this is not a real SKU and is just a way for Trunk to show that within this group there are variant SKUs that match this pattern, with the hashtags representing the characters that differ.
For example, if the variant SKUs are
SHIRT-RED
SHIRT-WHITE
SHIRT-BLUE
then the pattern would be SHIRT-###. Likewise if the variant SKUs are
5-PACK
10-PACK
25-PACK
then the pattern would be #-PACK.