Magnaflux Centrifuge Tube - 7C, 7HFMagnaflux 2461 Centrifuge Tube for Visible MPI Bath Monitoring The Magnaflux 2461 is a 100 ml ASTM pear shaped centrifuge tube used to monitor the bath concentration and contamination level of magnetic particles in Magnavis 7C and 7HF visible (non fluorescent) magnetic particle baths. Graduated from 0 to 1. 5 ml in 0. 10 ml increments, the 2461 provides the precise readings needed to maintain consistent bath strength and reliable inspection results.