Vallejo Mecha Color: Mecha Primer Grey (60ml)Vallejo 73. 641 Mecha Primer Grey Satin Airbrush Primer, 60ml Satin Primer for Gunpla, Miniatures, and Model Kits A neutral primer can make a big difference when you want clean color control without pushing the model too dark or too bright. Vallejo 73. 641 Mecha Primer Grey gives Gunpla, mecha kits, miniatures, resin parts, and model kits a balanced satin base that works well under almost any color scheme, from mechanical armor plates to fantasy