6mm Polyspring Insert, 300µL, Polypropylene, Conical Base, with Graduation Marks 2702N27 Mfr. No. C4010-S630 Description 6mm Polyspring Insert, 300µL, Clear Glass, National Scientific Silanized, Conical Base 2702N29 Mfr. No. C4010-627L Description 6mm Insert, Clear Glass, 350µL, Conical Base 2702N33 Mfr. No. C4010-629L Description