The brush washer ' s structure transforms from 4.5 " functional cup to " flat disk, fitting in pencil cases or art compartments without leakage Portable Paint Cup with foldable design artists a space saving solution for outdoor sketching and watercolor painting, functioning as both brush washer and portable water container Ideal for plein air, art students, and traveling creators requiring art supplies for mobile studios or classroom painting Crafted from premium food grade, this artists water cup maintains shape stability during use while remaining lightweight and for repeated folding / unfolding Perfect companion for landscape sketching in parks, watercolor workshops, or acrylic painting where easy clean brush