This masking fluid features a cap/wire system for non-clogging, air-tight and steady flow of fluid for smooth, endless lines. Ideal for use with acrylics, inks, gutta, watercolors, oil paints, silk dyes, stains, henna, water-based glues, glazes and other liquid media. The long stainless steel needle offers an easy-to-use, precise placement, free-flow, non-clogging masking fluid pen system. Available in packs of two 1.25 oz. bottles with 18- or 20-gauge needles.