When sourcing OEM baby diapers, you must prioritize the absorbent core technology, typically a mix of SAP (Super Absorbent Polymer) and fluff pulp. Ensure the absorption capacity meets your target market standards (e.g., 600ml to 1000ml for overnight use). Additionally, verify the use of breathable backsheets (cloth-like films) to prevent diaper rash and 3D leak guards to ensure side-leakage protection. For premium lines, look for S-cut magic tapes and elastic waistbands that provide a 360-degree fit.