Fuzan H1 is a tin-lead solder paste (Sn63Pb37 and Sn62Pb37Ag2 alloys, 89.5–90% metal load) built for stencil printing and reflow soldering on surface-mount lines. It contains no halogens and leaves clean, translucent residue that does not require post-solder washing, while still allowing solvent cleaning when appearance or high-reliability testing calls for it. The paste is formulated for exceptional print definition at fine pitch, long open/stencil life, and reliable tack retention between printing and placement, and it tolerates reflow peaks above the level typically required for many leaded alloys without loss of wetting performance. It meets or exceeds ANSI/J-STD-004 and J-STD-005 specifications and Bellcore test criteria, and is compatible with common conformal coatings. Supplied in 500 g jars (cartridge packaging available on request), the paste should be stored below 10 °C for a 12-month shelf life, warmed to room temperature for at least two hours before use. Manufactured in Russia by Ostec-Integra under TU 20.59.59-013-37241715-2023.