Your training focused on Crafting one particular kind of item. Select one of the specialties listed below; you gain a +1 circumstance bonus to Crafting checks to Craft items of that type. If you are a master in Crafting, this bonus increases to +2. If it's unclear whether the specialty applies, the GM decides. Some specialties might apply only partially. For example, if you were making a morningstar and had specialty in woodworking, the GM might give you half your bonus because the item requires both blacksmithing and woodworking. The specialties are alchemy (alchemical items such as elixirs, which requires Alchemical Crafting to Craft), artistry (fine art, including jewelry), blacksmithing (durable metal goods, including metal armor), bookmaking (books and paper), glassmaking (glass, including glassware and windows), leatherworking (leather goods, including leather armor), pottery (ceramic goods), shipbuilding (ships and boats), stonemasonry (stone goods and structures), tailoring (clothing), weaving (textiles, baskets, and rugs), and woodworking (wooden goods and structures).
Source: Pathfinder Player Core, p. 262
Bring Specialty Crafting into a Pathfinder 2e game with The DM Screen.