... -4236,EN71,CPSIA... 2,OEM client' logo 3,Ink can be seen only under uv light Promotional Invisible ... UV Pen with waterproof ink We are professional marker of pens manufacturer,owning ... ,furniture,leather,metal and any other smooth surfaces. Ink visible only under UV light,like the following pictures.Mini ... products. Promotional Invisible UV Pen with waterproof ink