Kester NF372-TB Flux-Pen� is a zero-halogen, no-clean, low solids flux available as a Flux-Pen� for rework of conventional and surface mount circuit board assemblies. - Kester NF372-TB flux passes IPC SIR testing in a raw or unheated state, ensuring Kester NF372-TB Flux-Pen�s can be safely used in rework applications, specifically those with high reliability requirements. NF372-TB Flux-Pen� residues are minimal, clear and non-tacky for improved cosmetics. NF372-TB Flux-Pen� is classified as ROL0 flux under IPC J-STD-004B.