Statstics on USA imports and exports, by commodity and trading partner. Free data is available as country level reports at one digit SITC level. More detailed data via:
(a) Censtats database interface: full detail SITC (subscription required)
(b) Selected Commodity Service: monthly reports based on users selection of 10 digit HS codes (subscription required)
Includes country-level trade balance data, Schedule B trade classification schemes codes