Replacement battery fits 6 BioControl compatible models. Specifications: 1800mAh, 10.8V, Ni-Cd. Compatible with: Air Sampler MAS-100, MAS-AC-6009, type MAS-AC-7009, Merck Millipore Air Sampler MAS-100, Merck Millipore MAS-AC-6009, Merck Millipore type MAS-AC-7009. Replaces: BioControl 110518-U, Merck Millipore 110518-U. BioControl replacement battery designed for Medical devices.