PC Flex Mask Regular Viscosity is a green single-component natural latex rubber that cures at room temperature.  This material is formulated to resist the adhesion of solder to specified areas of the circuit board during the soldering operation.  It will withstand temperatures up to 268C/515F during the normal soldering operation (not to exceed 5 seconds).  Once this material is used to mask the circuit board from solder, it is then manually peeled off and discarded. Other applications include sealing molds, masking conformal coating areas and holding components during wave solder.