Warren London Pawdicure Polish Pens- Neon Purple are water based, odorless, non-toxic, dry in under 40 seconds and are great for nail art! These Nail Polish Pens apply a quick drying, non-toxic, coat of polish that is easy to remove. Only one layer application is necessary for that great look for your pampered pup. On dark nails, we suggest doing a base coat of white first and then a color for a better result.