12 pack of disposable, white, rectangular filters measuring 3 1/2 inch by 1 1/2 inch to be used in Respironics REMstar Pro & Plus (both C-flex and non-C-flex models), REMstar Lite, REMstar Auto, BiPAP Plus & BiPAP Pro 2 and BiPAP ST.***Please Note***:   These filters do NOT fit the Remstar M Series CPAP Machines.