Calibrated loops 01850-00 and 01850-02 are ideal for milk samples. The 1-microliter loops are made of 26-ga B&S platinum wire with 15% iridium. The 10-microliter loops are calibrated and made of 19-ga B&S platinum wire with 5% rhodium. Order insulated loop and needle holder separately. Platinum loops and needles are used for transferring bacterial cultlres. These loops and needles are made of B&S platinum wire with 15% iridium added for rigidity, permitting a thinner wire for delicate work. Loops are fused to form a "perfect circle" with an inside tolerance of +/-0.02 mm to ensure accurate delivery. Order insulated loop and needle holder separetly.