Compact Attach asks the question before you buy the attachment

Why it surfaced

Compact Attach starts with the plate, not the product catalog: SSQA, John Deere hook-and-pin, Euro/global, or the pin dimensions required by a mini excavator. Its ROC calculator is explicitly a rule of thumb rather than a manufacturer rating, while the site openly labels its missing coupler checker and pin database as unfinished—a useful bit of honesty in an affiliate comparison site.

A fitment-and-comparison site for skid-steer and mini-excavator attachments, with an ROC calculator for checking attachment weight against rated operating capacity.