ALPHA 26F is an active, rosin/resin-free, low solids, no-clean flux. It is formulated with a thermally stable activator system, comprised of a proprietary activator system. The activators are designed to provide the broadest operating window from a low solids,no-clean flux, while maintaining a high level of long-term electrical reliability. After wave soldering, ALPHA 26F leaves no visible residue with most solder masks, which can be pin tested.