Hi,

To simplify your inventory of 66 distinct t-shirt product templates (each representing a unique color/size combination) into a single product template with 66 variants in Odoo 18.0, you should leverage Odoo's Product Attributes and Variants feature. First, define your attributes: create a "Color" attribute with 8 values (e.g., Red, Blue) and a "Size" attribute with 9 values (e.g., XS, S, M) under Inventory > Configuration > Attributes, ensuring the "Variant Creation Mode" is set to "Instantly" for both. Next, create a single new product template for your "T-Shirt" under Inventory > Products > Products, and on its "Attributes & Variants" tab, add both the "Color" and "Size" attributes, selecting all their respective values; Odoo will then automatically generate the 66 unique product variants. Finally, to transfer your existing data, export relevant information (like SKUs, barcodes, stock levels, and prices) from your 66 old product templates, map this data to your newly generated variants, and then import it back into Odoo to update the variants, after which you can archive or delete the original 66 product templates.