Buyers must prioritize Nitinal (Nickel-Titanium) wire material due to its superior shape memory and kink resistance, which is essential for navigating tortuous anatomy. The sheath diameter (typically measured in French, e.g., 1.5F to 3.0F) must be compatible with the working channel of the specific ureteroscope or endoscope being used. Additionally, verify the basket configuration (e.g., 4-wire, 6-wire, or tipless designs); tipless baskets are preferred for retrieving stones directly from the mucosal surface without causing tissue trauma.