Single-sided copper clad FR4 epoxy glass boards, with a positive working photo-resist coating, protected by a peel-off plastic film. Suitable for normal industrial and professional applications. Base laminate conforms to all international standards and releases, as lisited in IPC4101A.RoHS compliant.Specifications Thickness: 1.6mmCopper foil: 35 micronDissipation factor: 35Dielectric constant: 5.4Solderbath resistance (260°C): 20 secsResist thickness: 5 micronsSpectral response: 350-450nm, typical 2-3 minute exposureUV light energy required: Approx. 50mJ/cm Shelf life: 1 year at 15-20°C