The "standard" Aspect Finder is aligned with the eBay Item Specific mandates that are being rolled out and is currently FREE courtesy of eBay
More information on the specifics around mandates can be found in seller centre on the relevant regions, and eBay are announcing details regularly.
The benefits of adding aspects has been measured and published by eBay;
Dress listings with the item specifics “Style” and “Dress Length” completed, sell 81% more than those without.*
- Report comparing average sales value per listing for listings with item specifics “Dress Length” and “Style” vs those without from December 2017 - July 2018.
Optiseller's Aspect Finder + goes beyond the mandates, and allows users to apply these benefits across a wider range of categories and aspects.
Aspect Finder + is available in our paid-for plans, starting in the Essential plan - https://www.optiseller.com/pricing
Aspect Finder + will allow you to update all of the Item Specifics within the eBay mandated categories, and you can also now select any other categories that are outside the mandates.
If you select "Custom" you can then select up to 1,000 categories to process at a time.
The limit of 1,000 includes any sub categories of your selections.
If you need more than 1,000, then you can run multiple reports.